Skull and Mandible

The skull of LFGT-0103 is mostly complete. The anteroposterior length of the skull is 131.8 mm. The size of the skull in LFGT-0103 is smaller than that of the adult Coelophysis bauri (Colbert 1989; Reinhart et al. 2009), Megapnosaurus rhodesiensis (Raath 1977), and the Averostra-line Notatesseraeraptor frickensis (Zahner and Brinkmann 2019), and close to “S.” kayentakatae (Rowe 1989; Tykoski 2005; Tykoski 2005), and significantly larger than the juvenile C. bauri (Bugos and McDavid 2024). Based on the observation in other Coelophysoid specimens, the ratio between the lengths of the antorbital fenestra and the skull as a whole in LFGT-0103 is much larger than “S.” kayentakatae (Rowe 1989; Tykoski 2005), immature C. bauri (Bugos and McDavid 2024), Tawa hallae (Nesbitt et al. 2009), Herrerasaurus ischigualastensis (Sereno and Novas 1994), and Averostra-line neotheropods including N. frickensis (Zahner and Brinkmann 2019), Sinosaurus sp. (Hu 1993; Zhang et al. 2023), and Dilophosaurus wetherilli (Marsh and Rowe 2020), but close to mature individuals of C. bauri (Colbert 1989; Reinhart et al. 2009) and M. rhodesiensis (Raath 1977). The ratio between the dorsoventral height of the antorbital fenestra and the dorsoventral height of the skull in LFGT-0103 is 0.53, close to the average of members of Coelophysoidea including C. bauri (Colbert 1989; Reinhart et al. 2009) and M. rhodesiensis (Raath 1977), but relatively smaller than N. frickensis (Zahner and Brinkmann 2019), and significantly smaller than Tawa hallae (Nesbitt et al., 2009), H. ischigualastensis (Sereno and Novas 1994), and Averostra-line members Zupaysaurus rougieri (Ezcurra 2007), Sinosaurus sp. (Hu 1993; Zhang et al. 2023), and D. wetherilli (Marsh and Rowe 2020). Here, for Sinosaurus and D. wetherilli, the measurements do not include the dorsal crests over the skull.

In LFGT-0103, the shape of the orbit is subcircular, with a straight anterior border; this is similar to other members of the Coelophysoidea (Raath 1977; Colbert 1989; Rowe 1989; Reinhart et al. 2009), but different from T. hallae (Nesbitt et al. 2009), H. ischigualastensis (Sereno and Novas 1994) and Averostra-line members including Z. rougieri (Ezcurra 2007), genus Sinosaurus (Hu 1993; Zhang et al. 2023) and D. wetherilli (Marsh and Rowe 2020). In lateral view, the dorsal peak of the skull is at the posterior part of the frontal instead of the orbital level of the frontal. This is different from T. hallae (Nesbitt et al. 2009) and H. ischigualastensis (Sereno and Novas 1994), and the juvenile C. bauri (Bugos and McDavid 2024), but similar to the skull of mature C. bauri (Colbert 1989; Reinhart et al. 2009), M. rhodesiensis (Raath 1977), and ‘S.’ kayentakatae (Rowe 1989; Tykoski 2005), in which the skull reaches the highest point over the dorsal region of the frontal.

One important note regarding LFGT-0103 is that ossified elements are present in the anteroventral portion of the orbit. Based on the location of these elements, we assume the ossified elements could be partially preserved scleral ossicles. The boundary between each ossicle is not clearly visible due to poor preservation. The ossicles are located at the center of the orbit.

The mandible of LFGT-0103 is preserved, but the anterior and posterior tips are not visible. The teeth preserved in the maxilla and dentary were severely damaged during the preparation; the remaining parts of them are significantly smaller than other adult Coelophysoid specimens, including adults of C. bauri (Colbert 1989; Reinhart et al. 2009; Buckley and Currie 2014), M. rhodesiensis (Raath 1977), and “S.” kayentakatae (Rowe 1989; Tykoski 2005). In LFGT-0103, the mandible is mainly exposed from the right lateral side, with only partial observation of the left mandible from the medial side. The mandible of LFGT-0103 is mildly damaged on the lateral-medial side due to oppression. The length of the measurable part of the mandible is 111.2 mm.

In You et al. (2014), a well-marked external mandibular fenestra is labelled. Here we interpret the external mandibular fenestra in LFGT-0103 as more elongated than previously suggested and located at a more posterior and dorsal position than described in that study publication. An elongated external mandibular fenestra in the dorsal part of mandible is relatively common in early-derived dinosaurs and some neotheropods, including T. hallae (Nesbitt et al. 2009), H. ischigualastensis (Sereno and Novas 1994), N. frickensis (Zahner and Brinkmann 2019), but differs from the Coelophysoids M. rhodesiensis (Raath 1977) and “S”. kayentakatae (Rowe 1989; Tykoski 2005), and the stem-averostrans Z. rougieri (Ezcurra 2007), Sinosaurus sp. (Hu 1993; Zhang et al.,2023) and D. wetherilli (Marsh and Rowe 2020), which possess an external mandibular fenestra with much larger dorsoventral height and a much larger ratio between height and length. The presence of an external mandibular fenestra close to the posterior part of the mandible seen in LFGT-0103 is relatively common among neotheropods.

The preserved length of the dentary alveolar line with teeth preserved is 33 mm, and the ratio between the alveolar line and the total length of the mandible is about 0.297. This ratio is significantly smaller than the average ratio of neotheropods (Fig. 2).

Maxilla

Only the right maxilla is exposed in lateral view. The maxilla is composed of a ventral process and an ascending dorsal process. The maxilla is severely dislocated from its original position, with the posterior end of the ventral process reaching the posterior end of the skull from the ventral side of the quadratojugal. Based on C. bauri (Colbert 1989; Reinhart et al. 2009) and M. rhodesiensis (Raath 1977), the original location of the maxillary ventral process should join the ventral ramus of the lacrimal and the anterior border of the jugal. The maxillary fenestra and the promaxillary foramen are not visible in the anterior portion of the maxilla.

In the maxilla of P. lufengensis, one unique character is the distinct diagonal (=rostrodorsal-caudoventral) ridge over the lateral side of the medial lamina, which divides the lateral surface of the maxilla ventral to the antorbital fenestra into two parts, the dorsal part that composes the ventral border of the antorbital fenestra and the ventral part that participates in the external antorbital fenestra. This was listed as one of three diagnostic characters in You et al. (2014). On the contrary, based on the observations of other neotheropods, including Coelophysoids (Raath 1977; Colbert 1989; Rowe 1989; Tykoski 2005; Reinhart et al. 2009), Averostra-line neotheropods including Sinosaurus triassicus and Sinosaurus sp. (Hu 1993; Zhang et al. 2023), D. wetherilli (Marsh and Rowe 2020) and averostrans such as Allosaurus fragilis (Madsen 1976), Ceratosaurus nasicornis (Madsen and Welles 2000), the diagonal ridge in the maxilla is here interpreted as the pila interfenestralis, a common feature in many species. This ridge is absent in early-diverging dinosaurs such as T. hallae (Nesbitt et al. 2009) and H. ischigualastensis (Sereno and Novas 1994), as well as in Silesaurids. This distribution suggests that the diagonal or sub-parallel ridge is common among neotheropods but absent in other closely related groups, making it a possible apomorphic character of neotheropods. What is distinct in LFGT-0103 is that the pila interfenestralis is vertical, a first record in all neotheropods, making the orientation autapomorphic for P. lufengensis.

The posterior border of the maxillary ascending process forms the anterior border of the antorbital fenestra. The part of the process that contacts the lacrimal and the frontal is lost; however, the remaining ascending process still occupies more than half of the anterior border of both the external and internal antorbital fenestra. This is similar to members of Coelophysoidea (Raath 1977; Colbert 1989; Rowe 1989; Bugos and McDavid 2024), Sinosaurus triassicus and Sinosaurus sp. (Hu 1993; Zhang et al. 2023), D. wetherilli (Marsh and Rowe 2020), and Z. rougieri (Ezcurra 2007), in which the posterior end of the ascending process of the maxilla makes most of the antorbital fenestra. At the base of the dorsal process, four foramina are visible over the lateral surface. Three of the four foramina are located anterior to the diagonal ridge described in the last paragraph, and the one left is posterior to the diagonal ridge, anterior to the anterior angle of the internal antorbital fenestra. In You et al. (2014), the second character in the diagnostic characters combination is “the elliptical, laterally facing fenestra posterodorsal to the aforementioned diagonal ridge of maxilla.” In this research, this character is revised as follows – “the group of four elliptical, laterally facing foramina over the lateral surface of maxilla anterior to the antorbital fenestra, with one posterior to the aforementioned diagonal ridge of maxilla and three anterior to it.” The size of these foramina versus the size of the antorbital fenestra in LFGT-0103 is larger than the average ratio of the size of the promaxillary foramen versus the antorbital fenestra in other neotheropods, and their position is different from the promaxillary foramen in other neotheropods. However, it is highly possible that these foramina in P. lufengensis share the same origin as the promaxillary foramen in other neotheropods. The large foramen at the base of the ascending dorsal process in the maxilla is not observed in Coelophysoids (Raath 1977; Colbert 1989; Rowe 1989; Reinhart et al. 2009; Bugos and McDavid 2024) nor in N. frickensis (Zahner and Brinkmann 2019). In H. ischigualastensis, there is a foramen on the dorsal side of the dorsal process posterior to the external naris (Sereno and Novas 1994).

The preserved length of the maxillary ventral parallel process is 53.9 mm. In lateral view, the ventral process of the maxilla ends on the ventral side of the posterior end of the antorbital fenestra. The length of the preserved maxilla occupies more than 70% of the existing skull. Considering the disarticulation of the maxilla, the length of the antorbital fenestra would be larger than observed, and the maxillary alveolar line should be positioned in a more anterior position. Among early neotheropods and other dinosaurs, only some Coelophysoids (excluding M. rhodesiensis [Raath 1977]) and the early-deriving saurischian Eodromaeus murphi (Martinez et al. 2011) possess a maxilla with its alveolar line that extends to the ventral region of the orbit, which is different from what is observed in LFGT-0103. The posterior end of the maxilla is narrowed down into a tip. This is similar to other Coelophysoids such as C. bauri (Colbert 1989), “S.” kayentakatae (Rowe 1989), and most Averostra-line neotheropods such as D. wetherilli (Marsh and Rowe 2020), Sinosaurus triassicus (Zhang et al. 2023), and Averostrans such as Yuanmouraptor jinshajiangensis (Zou et al. 2025) and Asfaltovenator vialidadi (Rauhut and Pol 2019).

The preservation of the maxillary teeth is poor. Observation of the preserved maxillary teeth of LFGT-0103 shows that the morphology and anatomy of maxillary teeth are the same as the mandibular teeth, with the lingual end curving posteriorly, and serrations are present on both sides down to the base.

Nasal

The nasal could only be observed in dorsal and right lateral views, and most of its elements are lost. The preserved part of the right nasal contacts the counterpart at the midline of the skull, as expected.

Lacrimal

The lacrimal in LFGT-0103 is well-developed, sharing a similar morphology with other Coelophysoid taxa (Colbert 1989; Reinhart et al. 2009; Raath 1977; Rowe 1989; Tykoski 2005) and with the Averostra-line N. frickensis (Zahner and Brinkmann 2019) and S. triassicus (Zhang et al. 2023).

The right lacrimal is exposed in lateral view, slightly displaced. The lacrimal composes the dorsal margin of the antorbital fenestra and the anterior margin of the orbit. Due to disarticulation, the anterior process of the lacrimal is not connected to the nasal.

The length of the dorsal anterior process of the lacrimal is 11.7 mm, and the dorsoventral height of the ventral process is 20 mm. The dorsal body is slightly convex dorsally, and its width stays the same. This is same as what is observed in C. bauri (Colbert 1989; Reinhart et al. 2009; Bugos and McDavid 2024), but not only different from Coelophysoids M. rhodesiensis (Raath 1977) and “S.” kayentakatae (Rowe 1989; Tykoski 2005), and the early-deriving dinosaurs E. murphi (Martinez et al. 2011) and H. ischigualastensis (Sereno and Novas 1994), in which the lacrimal blocked the prefrontal from participating the anterior border of orbit, but also different from T. hallae (Nesbitt et al. 2009), in which the ventral process of lacrimal bifurcates at the ventralmost tip.

The ventral tip of the lacrimal contacts the dorsal process of the jugal. The ventral process of the lacrimal shows differences from other species of the Coelophysoidea members: the ratio of anteroposterior length between the external naris (measuring from the anterior tip to the posterior tip) versus the external antorbital fenestra (measuring from the anterior tip to the posterior border at midpoint) and the ratio of anteroposterior length between the external antorbital fenestra versus the orbit (measuring from the anterior border to the posterior border at the widest point) is close to “S.” kayentakatae (Rowe 1989; Reinhart et al. 2009), whereas the anteroposterior length of the external antorbital fenestra in M. rhodesiensis is much larger than other members of Coelophysoidea (Raath 1977).

The ventral process of the lacrimal is narrowed from the dorsal base towards the ventral tip, forming a triangular structure in lateral view. Close inspection shows small broken fractures over the anterior and anterodorsal border of the ventral process, indicating the possibility of an ossified fanlike structure that distinguishes the anterior portion from the posterior portion of the prefrontal. The ventral process of the lacrimal is similar to that observed in H. ischigualastensis (Sereno and Novas 1994), C. bauri (Colbert 1989; Reinhart et al. 2009; Bugos and McDavid 2024), M. rhodesiensis (Raath 1977), “S.” kayentakatae (Rowe 1989; Tykoski 2005), Dracoraptor hanigani (Martill et al. 2016), and S. triassicus (Zhang et al. 2023), but different from Z. rougieri (Ezcurra 2007). The length of the ventral process measured from its ventral tip to dorsal base is larger than the anteroposterior length of the lacrimal. The posterior border of the ventral process comprised most of the anterior border and a small portion of the dorsal border of the orbit. The posterior process of the lacrimal is reduced and contacts the prefrontal.

Prefrontal

The exposed right prefrontal includes an anterior and dorsal process that parallels the dorsal margin of the orbit, a ventral process that narrows and parallels the dorsal margin of the orbit, and a ventral process that narrows to the ventral tip. Compared to early-deriving Saurischians such as E. lunensis (Sereno et al. 1993; Sereno et al. 2013) and H. ischigualastensis (Sereno and Novas 1994), the prefrontal in LFGT-0103 is reduced in size and restricted to the anterodorsal border of the orbit, which appears to be the same as the short prefrontal observed in other Coelophysoids as well (Raath 1977; Rowe 1989). The main body of the prefrontal is bar-shaped and occupies the anterodorsal corner of the orbit and is mostly surrounded by the frontal at the medial and posterior borders. This is similar to what is observed in other Coelophysidae members such as C. bauri (Colbert 1989; Reinhart et al. 2009), “S.” kayentakatae (Rowe 1989; Tykoski 2005), and M. rhodesiensis (Raath 1977). In contrast, in Averostra-line neotheropods such as D. wetherilli (Marsh & Rowe, 2020) and S. triassicus (Zhang et al. 2023), the prefrontal occupies a larger portion in the formation of antorbital fenestra.

There is a small depression over the lateral surface of the prefrontal body in the anterior region, which represents the possibility that P. lufengensis might possess a pneumatic system over the lateral surface of the prefrontal. A similar structure over the prefrontal could be observed in the lateral surface of lacrimal and prefrontal of neotheropods such as the Coelophysids C. bauri (Reinhart et al. 2009) and “S.” kayentakatae (Rowe 1989), Averostra-line Z. rougieri (Ezcurra 2007), Sinosaurus sp. (Hu 1993), S. triassicus (Zhang et al. 2023), C. elloiti (Smith et al. 2007), D. wetherilli (Marsh and Rowe 2020), and Averostrans, especially in Allosauroidea such as Yangchuanosaurus hepingensis (Gao 1999) and Allosaurus fragilis (Madsen 1976).

Scleral Ossicle

In You et al. (2014), the ossified structure at the center of the orbit is not interpreted. In this research, after comparison, this bony structure is interpreted as the remnant of a scleral ossicle. The scleral ossicle is mostly deformed and compressed, leaving limited information concerning its development. The iridis in LFGT-0103 occupies a much smaller portion than what is observed in C. bauri (Colbert 1989; Reinhart et al. 2009) and “S.” kayentakatae (Rowe 1989; Tykoski 2005).

Postorbital

The postorbital is compressed slightly in the lateromedial direction. In lateral view, the postorbital is composed of the descending ventral process that composes the posterior border of the orbit and the dorsal body at the posterodorsal side of the orbit. The postorbital does not develop an elongated and slim anterior process as observed in Eoraptor lunensis (Sereno et al. 1993; Sereno et al. 2013), T. hallae (Nesbitt et al. 2009), H. ischigualastensis (Sereno and Novas 1994), CoelophysidaeC. bauri (Colbert 1989; Reinhart et al. 2009), and Averostra-line S. triassicus (Zhang et al. 2023). The dorsal body of the postorbital participated in the formation of the lateral border of the supra-temporal fenestra from its medial border, which is similar to other members of Coelophysidae (Raath 1977; Colbert 1989; Rowe 1989; Tykoski 2005; Reinhart et al. 2009; Bugos and McDavid 2024). The ventral process is mediolaterally thin, articulated in its posterior margin with the posterior ascending process of the jugal. The anterior border of the postorbital ventral process composes the entire posterior border of the orbit, and the lateral portion of its posterior process makes the anterodorsal border of the lower temporal fenestra. In the lateral view, the surface of the postorbital ventral process is slightly concave, and the anterior border of the ventral process is concave laterally. This ventral process contradicts the convex posterior border of the dorsal process of the jugal.

The anteroposterior length of the postorbital dorsal body is 24.9 mm, and the height of the ventral process is 28 mm, with a ratio between the two portions of 0.89. The postorbital of LFGT-0103 is overall similar to adult C. bauri (Colbert 1989; Reinhart et al. 2009), “S.” kayentakatae (Rowe 1989; Tykoski 2005), N. frickensis (Zahner and Brinkmann 2019), S. triassicus (Zhang et al. 2023), and D. wetherilli (Marsh and Rowe 2020), but larger than immature C. bauri (Bugos and McDavid 2024). However, the short anterior process in LFGT-0103 is similar to what is observed in “S.” kayentakatae (Rowe 1989; Tykoski 2005).

Frontal

The frontal is exposed dorsolaterally. The anteroposterior length of the frontal is 33 mm. The lateral border of the frontal makes up most of the dorsal margin of the orbit, while the anterior margin articulates with the preorbital, the anteromedial margin contacts the nasal, the posterolateral margin articulates with the postorbital, and the posteromedial margin contacts the parietal. On the dorsal side of the frontal, a sagittal ridge develops and forms the highest tip of the skull. This character is similar to adult C. bauri (Colbert 1989; Reinhart et al. 2009) and N. frickensis (Zahner and Brinkmann 2019). The ratio between the anteroposterior length of frontal versus the skull is 0.29, which is slightly smaller than adult C. bauri (Colbert 1989; Reinhart et al. 2009) and Averostra-line theropods such as S. triassicus (Zhang et al. 2023) and Averostra such as A. vialidadi (Rauhut and Pol 2019) and within the same range to E. lunensis (Sereno et al. 1993; Sereno et al. 2013), T. hallae (Nesbitt et al. 2009) and H. ischigualastensis (Sereno and Novas 1994).

On the posteromedial side of the frontal, which is the region that the frontal articulates with the parietal, a distinct sub-triangular depression is formed. This depression is the fossa of supratemporal fenestra, which is also documented on C. bauri (Colbert 1989; Reinhart et al. 2009), “S.” kayentakatae (Rowe 1989; Tykoski 2005), and N. frickensis (Zahner and Brinkmann 2019). As in other early-diverging dinosaurs and Coelophysoid species, the frontal in LFGT-0103 does not participate in the formation of the supratemporal fenestra. The lateral margin of the frontal forms a convex margin over the dorsal margin of the orbit, which extends to the prefrontal and postorbital. In “S.” kayentakatae, the frontal forms a lateral crest in this region (Rowe 1989; Tykoski 2005), and in M. rhodesiensis (Raath 1977) and C bauri (Colbert 1989; Reinhart et al. 2009; Bugos and McDavid 2024), the dorsal margin of the orbit is smooth.

Parietal

The parietal is exposed in lateral and posterior views. In lateral view, depression is visible continuously from the peak of the frontal sagittal ridge to the peak of the parietal sagittal ridge. In modern birds and crocodylians, this sagittal crest supports the occlusal muscles through the supratemporal fenestra and the lower temporal fenestra. This strongly developed sagittal ridge in P. lufengensis is the first one recorded in Coelophysidae, as taxa such as C. bauri (Colbert 1989) and M. rhodesiensis (Raath 1977) show a flat or slightly convex dorsal parietal surface. In both posterior and dorsal views, the supratemporal fenestra is sub-triangular, with its medial tip located at the lateral border of the parietal.

Jugal

Not originally labelled in You et al. (2014), the anterior tip of the jugal participates in the dorsoventral corner of the antorbital fenestra, and there is a weakly developed anterior ascending dorsal process visible laterally, which is supposed to contact the ventral process of lacrimal from its medial side. This indicates that the lacrimal and jugal articulate anteroventrally. Among other Coelophysoids, the jugal is barred from the antorbital fenestra by lacrimal, such as C. bauri (Colbert 1989; Reinhart et al. 2009), “S.” kayentakatae (Rowe 1989; Tykoski 2005), and M. rhodesiensis (Raath 1977). In contrary, this character is common among other dinosaurs, such as E. murphi (Martinez et al. 2011), H. ischigualastensis (Sereno and Novas 1994), T. hallae (Nesbitt et al. 2009), E. lunensis (Sereno et al. 1993; Sereno et al. 2013), and Averostra-line neotheropods such as N. frickensis (Zahner and Brinkmann 2019), D. wetherilli (Marsh and Rowe 2020), Z. rougieri (Ezcurra 2007), Sinosaurus triassicus (Zhang et al. 2023) and Cryolophosaurus ellioti (Smith et al. 2007).

The main body of the jugal is overlapped by the disarticulated maxilla, but the part that forms the ventral border of the orbit is visible. The posterior ascending dorsal process is distinct, measuring 21.1 mm from the ventral to the dorsal tip, only slightly shorter than the postorbital descending ventral process. In You et al. (2014), the parallel posterior process is interpreted as bifurcated, but here we observed that the jugal is not bifurcated in this region, which is similar to other members of Coelophysoidea, but different from other early saurischians, including H. ischigualastensis (Sereno and Novas 1994), E. murphi (Martinez et al., 2011), and early Averostra-line members, such as D. wetherilli (Marsh and Rowe 2020), Z. rougieri (Ezcurra 2007), Sinosaurus triassicus (Zhang et al. 2023) and Cryolophosaurus ellioti (Smith et al. 2007).

Quadratojugal

The quadratojugal is exposed in right lateral view. The quadratojugal contacts the squamosal from the posterior side of the dorsal ascending process in its dorsal portion. In the specimen, the quadratojugal is articulated with the jugal from the ventral side of the ventral process to the dorsal side of the posterior end of the jugal. The anterior process of the quadratojugal in LFGT-0103 is not elongated, only within the posterior border of lower temporal fenestra, which is different from H. ischigualastensis (Sereno and Novas 1994), E. murphi (Martinez et al. 2011), and early Averostra-line taxa including D. wetherilli (Marsh and Rowe 2020), Z. rougieri (Ezcurra 2007), Sinosaurus triassicus (Zhang et al. 2023) and Cryolophosaurus ellioti (Smith et al. 2007), which the quadratojugal possessed an elongated anterior process that formed the ventral border of lower temporal fenestra. However, it is similar to the quadratojugal in C. bauri (Colbert 1989; Reinhart et al. 2009) and M. rhodesiensis (Raath 1977) (Fig. 3).

Quadrate

The quadrate is only exposed in right lateral view. In this view, the dorsal head of the quadrate is subcircular, and the rest of the quadrate dorsal process has the same width as the dorsal head. This character is different from other neotheropods, as the more generalized pattern is that the width of the quadrate gradually narrows towards the dorsal head. However, it is impossible to rule out deformation during fossilization as the cause of this constant width in LFGT-0103.

Most of the lateral body of the quadrate is broad, making it fill most of the lower temporal fenestra. The exposed part of the quadrate in LFGT-0103 is much larger than what is observed in early theropods such as H. ischigualastensis (Sereno and Novas 1994), T. hallae (Nesbitt et al. 2009), and in other Coelophysids such as C. bauri (Colbert 1989; Reinhart et al. 2009).

Squamosal

The squamosal, visible in lateral and dorsal views, is composed of the anterior process on the dorsal side of the skull and the ventral process narrowing towards the ventral end. The anterior process of the squamosal participated in the lateral border of the supratemporal fenestra and the dorsal border of the lower temporal fenestra, while the ventral process participated in the posterior border of the lower temporal fenestra. The ventral process contacts the ascending process of quadratojugal from its posterior side, which is similar to C. bauri (Colbert 1989; Reinhart et al. 2009) and “S.” kayentakatae (Rowe 1989; Tykoski 2005), but different from M. rhodesiensis, in which the squamosal has a short ventral process (Raath 1977). The angle between the anterior process and the ventral process is about 80 degrees, which is larger than what is measured in specimens of C. bauri (Colbert 1989; Reinhart et al. 2009) and “S.” kayentakatae (Rowe 1989; Tykoski 2005), but similar to Averostra-line neotheropods, including N. frickensis (Zahner and Brinkmann 2019), D. wetherilli (Marsh and Rowe 2020), Z. rougieri (Ezcurra 2007), Sinosaurus triassicus (Zhang et al. 2023) and Cryolophosaurus ellioti (Smith et al. 2007). In lateral view, the squamosal in LFGT-0103 is similar to other members of Coelophysoidea except M. rhodesiensis (Raath 1977; however, the ratio of the length of the ventral process versus the length of the anterior process of LFGT-0103 is 0.82, which is much larger than other Coelophysoids except “S” kayentakatae (Rowe 1989; Tykoski 2005).

Palatine

The palatine is visible in lateral view, showing both the anterior portion within the antorbital fenestra and the posterior end ventral to the orbit. The anterior portion of the antorbital fenestra is not fully preserved, but the remaining part still occupies more than 50% of the anteroposterior length of the antorbital fenestra, and the dorsoventral height of the palatine occupies more than 50% of the antorbital fenestra. This ratio is similar to that of other Coelophysoids (Colbert 1989; Rowe 1989), as they have large vomers as well, but it is still larger than that of other species. However, since the skull is severely deformed, the actual portion of the palatine could be smaller. In C. bauri, the posterior end of the palatine stops anterior to the orbit (Colbert 1989). The round palatine posterior head in LFGT-0103 matches what is observed in M. rhodesiensis (Raath 1977; Colbert 1989).

Supraoccipital

The supraoccipital is exposed dorsolaterally. From the exposed part, the lateral surface of the supraoccipital is flat and smooth. The posterior part is displaced and deformed by the paroccipital process.

Paroccipital process

The paroccipital process is preserved and can be viewed laterally. In lateral view, the paroccipital process is flattened in cross-section. Since it’s not fully exposed, the total length of the paroccipital is not available. Comparing to related taxa such as C. bauri (Colbert 1989), M. rhodesiensis (Raath, 1977), and “S.” kayentakatae (Rowe, 1989; Tykoski 2005), the paroccipital process in LFGT-0103 is similar in shape and size, which is also observed in the paroccipital process of Averostra-line neotheropods, such as D. wetherilli (Marsh and Rowe 2020), D. hanigani (Martill et al. 2016), and S. triassicus (Zhang et al. 2023).

Sphenoid complex

The posterior portion of the skull includes the (para-)basisphenoid complex, exposed in lateral view. The basisphenoid is exposed in lateral view within the lower temporal fenestra. However, there are no observable characters preserved in this element due to the state of preservation (Fig. 4).

Dentary

The sutures between the dentary, the angular, and the surangular are unclear in LFGT-0103. The dentary groove is not visible over the lateral surface of the anterior portion of the dentary. The height of the maxilla remains basically the same until the second-to-last preserved dentary tooth. In LFGT-0103, the alveolar line starts expanding dorsally posterior to the second dentary tooth and ends at the last dentary tooth. In contrast, the ventral border of the dentary becomes concave, which happens more abruptly than in other saurischians, including T. hallae (Nesbitt et al. 2009), H. ischigualastensis (Sereno and Novas 1994), E. murphi (Martinez et al. 2011), Coelophysoidea, N. frickensis (Zahner and Brinkmann 2019), D. wetherilli (Marsh and Rowe 2020), but similar to E. lunensis (Sereno et al. 1993; Sereno et al. 2013).

Starting at the middle portion of the dentary, a groove is visible over the lateral surface of the mandible, which extends to the posterior end of it. The posterior end of the groove is divided by the external mandibular fenestra, then extends separately over the lateral surface of the angular and surangular. This groove does not develop gradually but appears suddenly at the anteroposterior midpoint of the dentary.

There are 11 teeth preserved in the dentary. The ratio between the length of the preserved mandibular teeth row and the measurable mandible is 0.297, and the ratio between the length of the mandibular teeth row and the maxillary teeth row is 0.88, which is close to other species of Coelophysoidea, but smaller than other neotheropods.

Angular

In LFGT-0103, the angular is severely deformed as most of the posterior part of the mandible is severely deformed and compressed. The angular articulates anteriorly with the posterior portion of the ventral margin of the dentary, forming the ventral margin of the external mandibular fenestra. The angular forms the posterior portion of the ventral border of that fenestra.

Surangular

In LFGT-0103, the surangular forms the dorsal rim of the external mandibular fenestra. The dorsal side of the surangular possesses a continuously ossified ridge extending from the dorsal side of the dentary. At the posterior tip of the mandible, the surangular is enlarged.

One unique character in LFGT-0103 is that the anterior dorsal process of the surangular formed the second-highest point of the whole mandible, and a concavity formed between this peak and the peak on the dentary. This is rare in neotheropods, as this is absent in other Coelophysoids (Raath 1977; Colbert 1989; Rowe 1989), Averostra-line taxa such as D. wetherilli (Marsh and Rowe 2020), S. triassicus (Zhang et al. 2023), and Averostrans such as Y. jinshajiangensis (Zou et al. 2025), and A. vialidadi (Rauhut and Pol 2019).

Splenial bone

In LFGT-0103, the left splenial bone over the medial side of the left mandible is exposed at its ventral end. From the exposure, the splenial bone is thin, a common pattern among archosaurs.

Prearticular

In LFGT-0103, part of the prearticular is visible, forming part of the internal mandibular fenestra. The posterodorsal border of the preserved prearticular is straight.

Vertebrae and ribs

The preserved axial series of LFGT-0103 consists of 12 cervical vertebrae, 13 dorsal vertebrae, and the first sacral vertebrae. Most of the cervical and dorsal ribs are broken and have lost their distal end, so it is impossible to determine their length (Fig. 5).

Cervical vertebrae

Due to the absence of ribs, we consider the last cervical vertebra to be the last vertebra that does not contact the scapula anterior to the scapula, which calculates up to 10 cervical vertebrae, including the atlas and axis. This number matches what is observed in C. bauri (Colbert 1989; Reinhart et al. 2009) and L. bonoi (Martinez and Apaldetti 2017) but is smaller than what is observed in Averostra-line dinosaurs such as Sinosaurus sp. (Hu 1993). The total length of the cervical series is 250 mm. The total length of the skeleton and the femur of LFGT-0103 is unknown, so it is not possible to determine the development of the cervical series in relation to the whole body.

In LFGT-0103, the atlas and axis are poorly preserved. The atlas is only partially exposed in lateral side. One certainty is that the width of the atlas is similar to the width of the axial centrum anterior surface.

You et al. (2014) gave the anteroposterior length of the axis as 18.5 mm, which we reaffirm. The neural spine of the axis is incomplete, and the centrum is exposed in anterior and lateral views. The prezygapophysis is broken and missing, leaving a circular cross-section over the anterodorsal surface of the axis.

Posterior to the axis, all eight cervical vertebrae in LFGT-0103 are preserved but only exposed in the right lateral view. There are gaps between cervical vertebrae VI, VII, VIII, and IX, clear broken edges presented over the cervical vertebrae VII and VIII, and the centrum anterior surface of cervical vertebrae IX. As measured in You et al. (2014), the anteroposterior length of centrum of cervical vertebrae from cervical vertebrate III to X is 24 mm, 28 mm, 29 mm, 31 mm, 30.5 mm, 28.5 mm, 28 mm and 23 mm. Comparing this data to L. bonoi (Martinez and Apaldetti 2017) and adult C. bauri (Reinhart et al. 2009), the cervical vertebrae of same position are on average 10% to 20% smaller in P. lufengensis.

In LFGT-0103, the cervical vertebrae in the middle of the column are elongated. Taking cervical vertebra IV as an example, the ratio between the anteroposterior length of the centrum and the height of the posterior articular surface of the centrum is about 2.77, and the ratio between the anteroposterior length and the total height of the vertebra, including the neural arch, is 1.45. This phenomenon is relatively common among early neotheropods, including Liliensternus liliensterni (Ezcurra and Cuny 2007), C. bauri (Colbert 1989; Reinhart et al. 2009), and L. bonoi (Martinez and Apaldetti 2017).

In lateral view, the margin of the anterior and posterior articular surfaces of cervical centra III to VI in P. lufengensis is nearly straight, and it is observed in at least cervical vertebrates V and VI that the centrum surface is depressed, which is the same as other neotheropods, including both Coelophysoidea and Averostra-line, but different from early-derived species, including H. ischigualastensis (Sereno and Novas 1994), Sanjuansaurus gordilloi (Alcober and Martinez 2010), and E. murphi (Martinez et al. 2011).

Panguraptor retains pronounced pleurocoels in the postaxial cervical vertebrae, with the most pronounced ones in vertebra VII. There are two pairs of pleurocoels over the lateral surface of the cervical vertebrae; the anterior pleurocoel of the centrum is shaped as a deep circular fossa, which possesses relatively straight dorsal and anterior margins. The posterior pleurocoel is located on the posterior centrum at a level anterior to the postzygapophysis and is shallow in its center. The anterior pleurocoel of cervical vertebrae demonstrates a different structure from C. bauri (Colbert 1989), M. rhodesiensis (Raath 1977), “S.” kayentakatae (Rowe 1989), and L. bonoi (Martinez and Apaldetti 2017) since these species preserved a shallow elliptical pleurocoel. There is no evidence of a small pleurocoel at the centrodiapophyseal lamina as observed in L. bonoi (Martinez and Apaldetti 2017). The presence of a ventral keel is observed in cervical vertebrae from III to X, which is also observed in L. bonoi (Martinez and Apaldetti 2017), C. bauri (Colbert 1989), and M. rhodesiensis (Raath 1977). The depth of the anterior and dorsal surfaces of the centrum in cervical vertebrae does not vary significantly, which is similar to C. bauri (Colbert 1989).

In Panguraptor lufengensis, the neural arches of the postaxial cervical vertebrae are ossified to the centrum. The ventrolateral articular facet of prezygapophysis articulates with the postzygapophysis of the previous vertebrate from its dorsomedial side. No clear depression or fossa is present over the lateral surface of the prezygapophysis and postzygapophysis of cervical vertebrae. The preserved neural spine of cervical vertebrae does not strongly develop in LFGT-0103 and forms a sail-shape fan on the dorsal side of the vertebrae. The diapophysis of cervical vertebrae is elongated anteroventrally, which is similar to other Coelophysoids (Raath 1977; Colbert 1989; Rowe 1989; Martinez and Apaldetti 2017). Starting from the cervical vertebrate VIII posteriorly, the length of the centrum shortens. The anteroposterior length of cervical vertebrate X is close to that of cervical vertebrate III. This shortening is common within Coelophysoidea (Raath 1977; Rowe 1989; Martinez and Apaldetti 2017). Unlike dorsal vertebrae, in the cervical vertebrae of LFGT-0103, the diapophysis projects ventrolaterally (Fig. 6).

Cervical ribs

The preservation of the cervical ribs is poor, and the lab repairs made the details difficult to observe. Among all preserved elements, cervical ribs III, IV, and VI are the most distinct. Three cervical ribs are closely articulated with corresponding cervical vertebrae, and their length basically matches their respective vertebrae as well. Cervical rib VI only preserved the proximal and distal ends.

Taking the right cervical rib IV and VI as examples. In cervical rib VI, part of the bone is lost during preparation as the mold of bone is still visible, but the tuberculum and the anterior process are in great condition. In comparison with the cervical rib preserved in C. bauri (Colbert 1989), the tuberculum of the cervical rib is located more anteriorly, constructing a steep angle with the rib’s anterior process. The height of two joints in cervical rib IV is slightly larger than the height of the anterior surface of the centrum in cervical vertebrate IV. In lateral view, the anterior angle region is concave. The lateral surface of the shaft of cervical ribs is convex and smooth, and the distal end is narrowed towards the midline.

One putatively autapomorphic character of P. lufengensis is the length of the cervical ribs, subequal to or slightly longer than the anteroposterior length of the centrum of the matching cervical vertebrate. In other species of the Coelophysoidea, the cervical ribs are significantly elongated (Raath 1977; Colbert 1989) and most of the later Averostra-line (e.g. D. wetherilli, as in Marsh and Rowe 2020) and even Averostra such as A. fragilis (Madsen 1976). This character could be considered as autapomorphic to P. lufengensis (Fig. 7).

Dorsal vertebrae

The dorsal portion of the vertebral column includes 13 vertebrae, exposed in right lateral view and partially in dorsal view. The vertebral column is continuously preserved, but most of the anterior dorsal vertebrae are at least partially covered by the right scapula, and the middle portion is not preserved well, which means that the dorsal vertebrae that could be measured for their length are dorsal vertebrae VIII to XIII. The length of their centrum is nearly constant throughout the series, with a variation within 2 mm, which represents the low compress rate in the posterior portion of the dorsal vertebrae. In average, the ratio between the anteroposterior length and the depth of anterior surface of centrum is 2.6, which is similar to or slightly smaller than E. lunensis (Sereno et al. 1993; Sereno et al. 2013), M. rhodesiensis (Raath 1977), P. milnerae (Spiekman et al. 2021), and C. bauri (Colbert 1989; Reinhart et al. 2009), but significantly larger than Liliensternus liliensterni (Ezcurra and Cuny 2007), L. bonoi (Martinez and Apaldetti 2017), and D. wetherilli (Marsh and Rowe 2020).

In lateral view, the lateral surface over the centrum of vertebrae in the middle to the posterior portion of the dorsal region is longitudinally depressed, and a ventral keel is absent. Although not fully exposed, the lateral margin of the centrum articular rim on the anterior and posterior sides appears to be straight. The parapophyseal centroprezygapophyseal fossa is visible and well-developed over the lateral surface of the neural arch in dorsal vertebrae, which forms a deep depression ventral to the diapophysis of the neural spine. This is common in other early neotheropods, including L. liliensterni (Ezcurra and Cuny 2007), Sarcosaurus woodi (Ezcurra et al. 2021), and Coelophysoids C. bauri (Colbert 1989), P. triassicus (Sereno and Wild 1992; Knoll 2008), M. rhodesiensis (Raath 1977), “S.” kayentakatae (Rowe 1989; Tykoski 2005), L. bonoi (Martinez and Apaldetti 2017), and P. milnerae (Spiekman et al. 2021). No distinct fossa is located over the dorsal region of diapophysis and parapophysis.

Most of the diapophyses are preserved, while the parapophyses are missing in most vertebrae. The suture between the neural arch and the centrum is closed in all vertebrae. In dorsal view, the diapophysis is complete in dorsal vertebrae from I to VIII, and their lateromedial length increases in sequence order. Starting at the dorsal vertebra VI, the posterior border of the diapophysis is slightly concave. The diapophysis is elongated laterally. The base and the lateral tip of the diapophysis are convex, and its cross-section is elliptical. At the base of the anterior border of diapophysis, the border slightly curves anteriorly towards parapophysis, showing a thin paradiapophyseal lamina, like what is observed in M. rhodesiensis (Raath 1977), Lophostropheus airelensis (Ezcurra and Cuny 2007), P. milnerae (Spiekman et al. 2021), and D. wetherilli (Marsh and Rowe 2020). In general, the structure of the neural arch in LFGT-0103 is similar to C. bauri (Colbert 1989; Reinhart et al. 2009) and M. rhodesiensis (Raath 1977), but slightly different from P. milnerae (Spiekman et al. 2021).

The neural spines are poorly preserved and prepared in the anterior column. In dorsal view, the dorsal margin of the neural spine is nearly flat, with straight anterior and posterior border that slightly overhangs posteriorly. The anteroposterior length of neural spines increased dramatically starting from dorsal vertebrate I and remained relatively the same from dorsal vertebrate IV. Based on dorsal vertebrae VI to XIII, the ratio between the length of neural spine versus the length of centrum is close to C. bauri (Colbert 1989; Reinhart et al. 2009), and P. milnerae (Spiekman et al. 2021), but slightly larger than “S.” kayentakatae (Rowe 1989; Tykoski 2005) and M. rhodesiensis (Raath 1977).

Trunk ribs

The trunk ribs are not preserved, and the dorsal ribs I to VIII are preserved. Most of the preserved ribs lost their distal ends, and their proximal ends are compressed by other bone elements. In LFGT-0103, ribs V, VI, and X are the best preserved and exposed, so most of the information comes from them. In lateral view, the tuberculum of rib VI is elongated, with a relatively weakly developed centrum joint that forms a straight border between the two elements. Compared to this, the tubercle joint in rib X is distinctively smaller. In rib V and X, the angle formed by the anterior tubercle joint and posterior centrum joint forms a distinct deep groove along the lateral surface of the rib. The shafts of the ribs are sub-elliptic in cross-section, which is different from Averostra-line neotheropods such as S. woodi (Ezcurra et al. 2021) and Sinosaurus sp. (Hu 1993). From the observation of the remaining elements, the rib in LFGT-0103 matches the general aspect of other neotheropods.

Sacral vertebrate

The first sacral vertebrate is partially obscured by the ilium laterally. Though not much can be gathered from the specimen, based on other Coelophysoids such as C. bauri (Colbert 1989), M. rhodesiensis (Rowe 1989), and P. milnerae (Spiekman et al. 2021), there shall be four or five sacral vertebrae in P. lufengensis. This number matches what is observed in some other Averostra-line neotheropod such as Sinosaurus sp. (Hu 1993), but more than D. wetherilli (Marsh and Rowe 2020).

Pectoral girdle and forelimbs

Only the right scapula is fully preserved and exposed. The right forelimb is mostly preserved (Fig. 8).

Pectoral gridle

The right scapula is fully exposed in right lateral view; however, the posterior margin of the bone is not fully preserved. The total anteroposterior width of the scapula is 34.2 mm, and the dorsoventral height (measuring from the dorsal border to the lowest border of ventral processes) is 84.7 mm, making the ratio between the height and the length as 2.48. This ratio is larger than that of adult C. bauri (Colbert 1989; Reinhart et al. 2009) but much smaller than E. murphi (Martinez et al. 2011) and more derived D. wetherilli (Marsh and Rowe 2020). The narrowest point of the scapula (= “scapula neck”) is located at a point a quarter from the ventralmost tip. In other Coelophysoids, the scapula possesses a more distinct neck that is about half as wide as the widest part of the scapula. In this case, LFGT-0103 is more similar to Averostra-line taxa such as D. wetherilli (Marsh and Rowe 2020) and S. sinensis (Hu 1993). Dorsal to the narrowest point of the scapula, the scapula expands anteroposteriorly starting from the dorsal margin and reaches the widest point at about one third of the total length, then narrows down towards the narrowest point (Fig. 9).

A distinct, rounded ridge is developed over the lateral surface of the dorsal margin of the scapula. In lateral view, the ridge narrows and rises from its anterior tip to its posterior end. The lateral ridge over this region of the scapula in neotheropod species is the first-time record, and this character is yet to be found in other dinosaur and dinosauromorph species. In this research, this character is labeled as the autapomorphic character of P. lufengensis. The lateral surface of the scapula, ventral to the ridge, is smooth and concave towards the posteroventral edge of the scapula, forming a rounded anterodorsal margin in the scapula. The posterior margin of the scapula (=scapula blade in some research, e. g., Marsh and Rowe 2020) is straight, which is different from C. bauri (Colbert 1989), which possesses a convex margin of scapula, but similar to Averostra-line neotheropods, including D. wetherilli (Marsh and Rowe 2020).

Over the lateral surface of the scapula, below the fossa subscapularis, in lateral view, the glenoid fossa is well-developed, with a distinct acromion and a strong attachment for the triceps brachii muscle. In comparison, most neotheropods do not possess such a strong attachment for the muscle, as observed in Coelophysoidea (Raath 1977; Colbert 1989; Rowe 1989), D. wetherilli (Marsh and Rowe 2020), and even in Averostra such as A. fragilis (Madsen 1976).

On the ventral side of the scapula, part of the coracoid bone is visible. The coracoid bone is not fused with the scapula. The glenoid fossa on the coracoid is not visible.

The forelimb

The right forelimb is preserved and mainly exposed in lateral view. The preserved elements in this specimen include the right humerus, ulna, radius, metacarpals, and manus phalanges I – IV.

The right humerus is incomplete. The mediolateral width of the shaft narrows from the proximal to the distal end. The anteroposterior width of the humerus is the shortest at the point right ventral to the deltopectoral crest, where the cross-section of the shaft becomes sub-circular instead of flat elliptical. At the distal end, both the medial and the lateral condyle are exposed mainly in distal view. Both condyles are semi-spherical in shape, with similar size, as in C. bauri (Colbert 1989), M. rhodesiensis (Raath 1977), and FNMH CUP-2089 (Irmis 2004), but different from Averostra-line N. frickensis (Zahner and Brinkmann 2019) and D. wetherilli (Marsh and Rowe 2020).

The ulna and radius are mainly exposed in anterolateral view, with the right radius severely broken. As observed in other neotheropods, the length of the radius is gently shorter than the ulna. In lateral view, the widths of the ulnar and radial shafts are similar and of constant width. This is different from some subadult C. bauri (Reinhart et al. 2009) as the width of the radius and ulna are different, but the same as what is observed in M. rhodesiensis (Raath 1977). In proximal view, the olecranon of the ulna is sub-triangular in shape, which matches the description of FNMH CUP-2089 by Irmis (2004). The ulnocarpal joint is preserved in LFGT-0103; however, no significant characters can be observed.

Based on our interpretation of metacarpal identity, the manus possesses four digits, I-IV. All digits can be observed in ventral (= palmar view in some research, e.g., Barta et al. 2017) and lateral views. In ventral view, the width of metacarpal II is as mediolaterally wide as metacarpals III and IV combined. The proximodistal length of metacarpal IV is smaller than half of metacarpal II and III. Over the medial surface of metacarpal III is the slim metacarpal IV, which is shorter than metacarpals II and III.

The phalanx 1 of digit I is not fully exposed, but the proximodistal length of phalanx I-1, from the proximal articular surface to the distal condyles, is similar to that of phalanx II-1, making both phalanges the longest in the manus. The ungual of digit I, similar in length to phalanx 2, digit II, is compressed lateromedially, curved ventrally as observed in other small neotheropods, and the collateral groove is visible on the lateral side. The flexor tubercle is visible on the lateral side, bounding the collateral groove mentioned above. The ungual of digit II is not fully exposed, but from the exposed lateral surface, the size of the ungual on digit II is smaller than the ungual on digit I. Three phalanges of digit III could be observed, with the manual phalanx 3 of digit III elongated, but the ungual is missing. Only the first phalanx of digit IV is visible in lateroventral view, and as stated by You et al. (2014) and based on the morphology of other Coelophysoids, the distal end of digit IV is not ungual, but instead a shortened cone-shaped phalanx bone. In conclusion, the pattern of manual phalange in P. lufengensis is 2-3-4-1-X, which matches the record in other species of the Coelophysoidea (Raath 1977; Colbert 1989).

Pelvic gridle

Parts of the right ilium and of both ischia are preserved (Fig. 10).

Ilium

The right ilium of LFGT-0103 is only exposed in lateral view. However, based on a group of old photos acquired from Dr. Hailu You, it is demonstrated in at least one photo that at some point before 2011, the ilium was removed from the skeleton and fixed into a complete specimen. In the remaining photos, the restoration of the right ilium was based on a generalization of the common morphology of neotheropods. In this research, the description of the ilium will be based on both the current situation of the ilium and the photos.

Only the middle portion of the ilium is preserved, which includes most of the acetabular region from the preacetabular process to the antitrochanter. In lateral view of LFGT-0103 and the photos, the preacetabular process in LFGT-0103 is elongated and narrowed to a point anteriorly, the dorsal rim of iliac blade is slightly convex. The lateral surface of ilium dorsal to acetabular rim is smooth and gently concave, which is observed in other neotheropods, such as the concave surface observed in Coelophysoidea species “S.” kayentakatae (Rowe 1989).

In lateral view, the pubic peduncle is stronger and more developed than the ischiadic peduncle, which is common among Coelophysoidea (Raath 1977; Colbert 1989; Rowe 1989; Martinez and Apaldetti 2017; Ezcurra 2017; Spiekman et al. 2021).

In recovered pictures, in the medial view, the cross-sectional shape of both pubic and ischial peduncles is sub-triangular. The anteroposterior width of the pubic peduncle remains basically the same dorsoventrally. In contrast to this, the ischiatic peduncle is blade-shaped at the posterior end, expanding into a sub-rectangular cross-section in the middle with an expansion in width. This blade-shaped ischiatic peduncle is unique for P. lufengensis but could be explained by deformation during fossilization. In medial view, the angle formed between both peduncles is around 70 degrees. The ischiatic peduncle is more ventrally developed, but the broken gap indicates that this is highly likely due to deformation. The attachment scar for the sacral vertebra and sacral rib is not observable on the medial side (Fig. 11).

Ischium

The shaft and distal end of the paired ischium could be observed from the lateral side, displaced posteriorly in relation to the right femur. The shaft reaches the maximum width at the anterior-most part of the shaft, and then gradually narrows down towards the distal end, which has a teardrop-shaped expansion. Both the lateral and the medial surfaces of the ischium shaft are gently concave. The distal ends of the ischia only contact each other at their medial surface. The distal end of the ischium forms an enlarged boot. This is different from M. rhodesiensis (Raath 1977), in which the distal head of the ischium does not form an enlarged head at its posterior end, but is similar to the distal “boot” of the ischia in D. wetherilli (Marsh and Rowe 2020) and Sinosaurus sp. (Hu 1993).

Hindlimb

In LFGT-0103, most elements of the right hindlimb are preserved. Only one left phalanx is visible, below and mostly obscured by the ischia. The right femur is completely preserved. The femoral head is still housed in the acetabular rim of the ilium, and the femoral distal end still articulates with the proximal end of the tibia and fibula. The tibia and fibula are exposed mostly in lateral view, with both proximal and distal ends present, the fibula being better exposed throughout. The distal end of the tibia and fibula still articulates with the proximal end of the astragalus, calcaneum, fused distal tarsal III, and distal tarsal IV. The right pes preserves the pedal digits III, IV, and V.

The right femur is broken and missing a small portion in the middle part of the shaft. The length of the proximal and distal parts is 95.9 mm and 69.5 mm, respectively. Measured in lateral view, the width of femoral distal condyles is 16.4 mm, the width of the distal broken edge in the proximal portion is 13.1 mm, while for the proximal broken edge of the distal portion is 11.5 mm. The femoral head is enlarged proximally in lateral view, articulating with the pelvic girdle from the proximal, anterior, and medial side. The femoral shaft bends proximally at the level of the greater trochanter, and then bends anteriorly at the point distal to the femoral head, which is observed in other Coelophysoids (Raath 1977; Colbert 1989; Rowe 1989; Ezcurra 2017; Spiekman et al. 2021; Kirmse et al. 2023) and D. wetherilli (Marsh and Rowe 2020), but different from other Averostra-line neotheropods such as D. hanigani (Martill et al. 2016) and N. frickensis (Zahner and Brinkmann 2019), in which the shaft is straight distally from the greater trochanter. The proximal margin of the femur is rounded. Posterior to the ligament fossa is a distinct dorsolateral trochanter. The dorsolateral trochanter is a ridge-shaped structure with the direction parallel to the femoral shaft, which is similar to the femur of M. rhodesiensis (Raath 1977) and P. milnerae (Spiekman et al. 2021), but different from C. bauri (Colbert 1989) and “S.” kayentakatae (Rowe 1989). The ridge-shaped dorsolateral trochanter in LFGT-0103 matches the flange-shaped dorsolateral trochanter discussed by Griffin (2018), thus could be labeled as an intermediate level of maturity.

Over the anterolateral surface of the femur stands the anterior trochanter (=lesser trochanter, e.g. Raath 1977). In LFGT-0103, the trochanter shelf does not connect to the linea intermuscularis caudalis in lateral view, indicating it’s far from reaching skeletal maturity, but the presence of the shelf itself indicates the individual is not juvenile, either. Comparing the femur in LFGT-0103 to the result concerning the ontogeny of neotheropods in Chinsamy-Turan (1990), Reinhart et al. (2009), Griffin (2018), Griffin (2019), Spiekman et al. (2021), and Barta et al. (2022), it is reasonable to assume that LFGT-0103 demonstrates the characteristics of an intermediate level between juvenile and full maturity.

The femoral shaft is gently convex anteroposteriorly, with the width at the anterior side basically equals to the width proximal to the dorsolateral trochanter and gradually reduced towards the distal end, which is similar to what is observed in C. bauri (Colbert 1989), M. rhodesiensis (Raath 1977), S. woodi (Ezcurra et al. 2021), L. liliensterni (Ezcurra and Cuny 2007), and D. wetherilli (Marsh and Rowe 2020). In lateral view, the distal end is round in outline, and the lateral condyle is directly connected to the shaft. In distal view, the lateral condyle is sub-triangular in shape. The medial condyle cannot be observed. In LFGT-0103, the distal end of the femur shares the same condylar structures as in FNMH CUP-2090 preserved in the Field Museum of Chicago (Irmis 2004), but different from FNMH CUP-2090 as the size of femur in LFGT-0103 is much larger. In lateral view, the lateral condyle of femur possesses a fossa on the lateral side and shows as a circular-shaped distal margin. This is also seen in other Coelophysoids (Raath 1977; Colbert 1989; Hunt et al. 1989; Rowe 1989; Spiekman et al. 2021) (Fig. 12).

The fibula is broken into three pieces. The length of the proximal section is 19.6 mm, the midshaft section is 114.9 mm, and the distal section is 34.7 mm. The estimated complete length of the fibula is about 170 to 175 mm. The tibia is slightly longer than the fibula, with the length of exposed region of 179.9 mm. In proximal view, the cross-section of fibula proximal end is C-shaped, with an anteroposterior groove which could be possible for articulating with the distal lateral condyle of femur proximally. The proximal end of the tibia is sub-triangular, and when both proximal ends articulate, the two elements together form a sub-rectangular shape articular facet for the distal femur. The anteroposterior length of the tibiofibular proximal articulatar surface is 36 mm, and the lateromedial width of the surface is 33.7 mm. Measuring at the midpoint of both elements, the anteroposterior width of fibula proximal end is 24.8 mm, when it comes to the fibular shaft, the width is 6.8 mm, and the distal end is 11 mm. The distal end of fibula is much smaller than the proximal end, which is common among Coelophysoids, as observed in mature specimens of C. bauri (Colbert 1989) and “S.” kayentakatae (Rowe 1989). The anteroposterior width of tibia proximal end is 33.7 mm, and the distal end is 16.1 mm. The distal end of tibia is not fully exposed and thus can’t be measured. The fibular crest is presented over the anteromedial side of the proximal tibia, which also possesses a groove between the crest and the proximal surface. In lateral and proximal views, the hook-shaped fibular crest is strongly developed, which is the same as what is observed in P. podocitus (Ezcurra 2017). The shafts of both tibia and fibula are nearly straight. The major difference between LFGT-0103 and C. bauri is that the fibular crest in LFGT-0103 is sharper and more developed than what is observed in C. bauri (Colbert 1989). The tibia and fibula in LFGT-0103 match the character described in FNMH CUP-2090 (Irmis 2004) and also in M. rhodesiensis (Raath 1977), C. arizonensis (Ezcurra and Brusatte 2011), and “S.” kayentakatae (Rowe 1989).

Distally to the tibiofibula, the lateral surface and partial distal end of the astragalocalcaneum are observable. The exposed lateral surface is semi lunate, and the anterior ligament fossa is clearly visible over the surface. The lateral end of the calcaneum is also exposed, and it develops a relatively shallow groove on its surface. Besides these elements, part of the proximal end of fused distal tarsal III and the distal end of fused distal tarsal IV are exposed, with a diagonal groove developed over the lateral surface of the proximal end of fused distal tarsal IV. All the elements are unfused: not only are the astragalus and calcaneum not fused, but also the distal tarsals are not fused to the metatarsals. This demonstrates an earlier stage of ontogeny, as stated by Griffin (2018), in contrast with what is observed in the femur, which suggests the ossification order in Panguraptor was different from the ones discussed in that publication, further adding to the diversity of ontogenetic development patterns (Griffin et al. 2021). In proximal view, the proximal end of distal tarsal IV possesses a sub-triangular hook structure, which is mentioned in earlier research by You et al. (2014) and listed as part of the diagnostic character. We confirm here that such a hook is autapomorphic to P. lufengensis among neotheropods. However, the proximal end of distal tarsal IV in D. wetherilli does not form a hook structure but possesses a strongly pointed margin instead. A similar structure is observed in D. wetherilli (Marsh and Rowe 2020). However, the proximal end of distal tarsal IV in D. wetherilli does not form a hook structure but instead possesses a strongly pointed margin.

The right pes is well preserved; however, only metatarsals IV and V, a part of pedal phalanx III, and the complete pedal phalanx IV are sufficiently exposed for meaningful description. The complete length of metatarsal IV is 99.5 mm, and for metatarsal V is 40.8 mm. The ratio between the length of metatarsal V and metatarsal IV is 2.46, which is close to that of C. bauri (Colbert 1989). The proximal end of the metatarsal is sub-triangular, and the lateral surface of metatarsal IV is an elongated subtrapezoidal, with the margin narrowing toward the posterior end. The development of metatarsal V in LFGT-0103 is common among small neotheropods, including C. bauri (Colbert 1989) and other neotheropods, but rare among middle- to large-size neotheropods such as D. wetherilli (Marsh and Rowe 2020) (Fig. 13).

Both pedal digits III and IV preserved four phalanges, including the ungual in digit III but not in digit IV. Medial to phalanx IV-1, the distal condyles of a phalanx are visible, which could be the phalanx I of pedal digit II based on its position. A deep groove is carved between the distal condyles of phalanx I of pedal digit II, which also shows deep ligament fossae on the lateral side. The lengths of the three phalanges preserved in pedal digit III, besides the ungual, are 19.9 mm. 13.4 mm and 13.4 mm, while the lengths of the three phalanges in pedal digit IV are 27.1 mm, 24 mm, and 21.6 mm. The ratio between the total length of the three phalanges of pedal digit III versus pedal digit IV is 0.64, which is slightly smaller than C. bauri (Colbert 1989) and M. rhodesiensis (Raath 1977), indicating a larger difference in length between two pedal digits. The length of the ungual of pedal digit III is 16.7 mm. Phalanges 2 and 3 of pedal digit III are partially exposed laterally, showing that the ventral width of distal condyles is larger than the dorsal width and the phalanx have a sub-circular shaft. There is only one groove visible over the lateral surface of the ungual of pedal digit III. In all the phalanges of pedal digit IV, the width of the proximal articular surface is only slightly larger than that of the distal condyles, and the shaft narrows just proximal to the condyles, with a width only slightly smaller than the distal end. What is observed in LFGT-0103 is similar to what is observed in C. bauri (Colbert 1989) and M. rhodesiensis (Raath 1977), as in both species, the pedal phalanges demonstrate similar patterns in their size and relationship to one another.