(amended from Nursall 1996, 2010 and Poyato-Ariza and Wenz 2002). Basal Pycnodontiformes with the following unique combination of characters: scales imbricate (cover the whole body); jagged sutural connections between trunk scales; cheek region covered by small, ovoid or elongated scales; cheeks covered by a mosaic of irregular polygonal dermal elements, anterodorsally the snout covered by heavier polygons (partly covering the frontal), all decorated with irregularly arranged, rounded tubercles; dermal bones of the skull and most body scales decorated with tubercles; plane of vomer approximately horizontal; caudal fin with a rounded or straight posterior margin (unknown for Aminiichthys leedsi); caudal peduncle large with multiple scales rows in adult specimens.

Mesturus Wagner, 1862; Micropycnodon Hibbard & Graffham, 1945; Aminiichthys new and Goodichthys new.

Contrary to Nursall (1996), the genus Arduafrons is not within the Mesturidae, as became apparent in the phylogeny of Kriwet (2001), Poyato-Ariza and Wenz (2002) and the here presented phylogenetic analysis.

Mesturus verrucosus Wagner, 1862.

Middle to Upper Jurassic (Callovian to Tithonian).

As for Type and only species.

SNSB-BSPG AS V 508 (Fig. 2).

Eichstätt, Solnhofen Archipelago, Bavaria, Germany.

Lower Tithonian (Hybonotum Zone, Ridense Subzone, eigeltingense β Horizon).

JME-SOS3309a,b (from Eichstätt); NHMUK PV OR 37023 (from Solnhofen; Fig. 3); LF 1980 (from Eichstätt; Fig. 4A); MB.f.19903 (cast; Solnhofen Archipelago; Fig. 4B); LF 1968 (from Eichstätt; Fig. 5); LF 3446 (from Daiting; Suppl. material 1: fig. S1); Collection Bastelberger (from Painten; Suppl. material 1: fig. S2); Coll. Gehrer (from Painten, Fig. 6); CHT 94/1 (from Eichstätt; Frickhinger 1999, figs 196, 197; Arratia and Schultze 2015, fig. 756; fig. S3).

(see Fig. 1B, C). Daiting (early Tithonian, Hybonotum Zone, Moernsheimensis Subzone, moernsheimensis horizon); Solnhofen (early Tithonian, Hybonotum Zone, Rueppellianus Subzone); and Painten (late Kimmeridgian, Beckeri Zone, Ulmense Subzone, rebouletianum horizon).

As can be seen in the synonym list above, this article excludes some specimens, which have been described by other authors under the species name “M. verrucosus” (Frickhinger 1991, 1994; Lambers 1992; Kriwet 2000, 2001, 2005; Poyato-Ariza and Wenz 2002; Arratia and Schultze 2015). These specimens are described below as Goodichthys prettii gen. et sp. nov.

(amended from Wagner 1862; Woodward 1895; Nursall 1996; Kriwet 2001; Poyato-Ariza and Wenz 2002). Large, basal Pycnodontiformes reaching 51 cm total length (45 cm SL), with the following unique combination of characters: Body ovoid in lateral aspect; dorsal and anal fin rounded with the highest part in the centre, in adult specimens comparably low; caudal fin with convex posterior margin; dermal skull elements irregularly arranged including a variable number of marginal bones on the anteroventral part of the frontals to the premaxilla; vomerine and prearticular teeth smooth (without crenulations), but with median ridge (90° to body axis); maxilla ornamented; dorsal fin supported by 27–31 pterygiophores; anal fin supported by 23–24 pterygiophores; scale rows of the body bifurcating towards the whole of the dorsal margin and towards the caudal half of the ventral margin; scale rows change direction and become smaller in front of the dorsal and anal fin; anteriormost three or four dorsal ridge scales larger than subsequent dorsal ridge scales; scales extend between bases of fin rays.

Remarks. The species Mesturus verrucosus was described in detail by Wagner (1862), Woodward (1895) and Nursall (1999a). However, today, we have new insights thanks to recent discoveries, especially from juvenile specimens (Figs 5, 6, 7, 8, 10B, 11, Suppl. material 1: figs S2–S5). Here, I will focus on the juveniles and explain the differences to the adult specimens described so far. In my opinion, the differences in the juveniles are primarily due to ontogeny. Other features are only visible in juveniles, because, in adults, these features are covered by massive scales. My assumption that the adults and juveniles are one species is based mainly on the same number of scale rows on the body and the same number of dorsal and anal pterygiophores.

General morphology and size. In this article, I describe for the first time juvenile specimens of Mesturus verrucosus of 38–87 mm (TL) and 31–73 mm (SL). Adult specimens can reach sizes that rank amongst the largest known Pycnodontiformes (only Gyrodus circularis grows larger); all five known adult specimens have a total length (TL) between 435 and 507 mm and a standard length (SL) between 385 and 453 mm (for measurements of specimens, see Suppl. material 1: table SS1). Specimens in size between these large specimens and the juveniles are unknown. The maximum body depth is 62–67% of standard length (SL) in adult specimens and 79–94% in the juveniles. The deepest part of the body is in the middle between the dorsal fin and the cranium.

Body shape. In juveniles of M. verrucosus the body shape is with 70–94% standard length to body depth (SL/BD) even more rounded than in adults with 62–67%. The taxon Goodichthys, formerly classified as M. verrucosus, is much more elongated with 52–57% SL/BD and for this reason alone cannot be considered an intermediate form between the juveniles and the adult animals of M. verrucosus.

Cranium. A drawing of the cranium of the specimen NHMUK PV OR 37023 of Mesturus verrucosus was given by Woodward (1895, pl. 15; see Fig. 3), Lehman (1966, fig. 164), Nursall (1999a, fig. 3) and Taverne (2014, fig. 2). In this article, I will therefore not describe the skull of M. verrucosus in detail again; instead, I will only describe some differences from what is known so far and show drawings of the skulls of the juveniles LF 1968 (Fig. 7) and the Bastelberger specimen (Fig. 8).

Maxilla. The maxilla is ornamented and broad. The ornamentation is best visible in NHMUK PV OR 37023 (Fig. 3), the LF3446 (Suppl. material 1: fig. S1) and the juvenile Bastelberger specimen (Fig. 8). Based on NHMUK PV OR 37023, Nursall (1999a, p. 155, fig. 3; 2010), Poyato-Ariza and Wenz (2002) and Kriwet (2005, fig. 24J) thought the maxilla of Mesturus verrucosus was elongated or at least twice as long as wide. However, I think the ventral border of the maxilla in NHMUK PV OR 37023 was broken and originally much broader, which is normal for Pycnodontiformes (Kriwet 2005, fig. 24). The maxilla is rounded in shape, with a broad anterior extension connecting to the premaxilla (Fig. 8). The shape of the maxilla is best visible in LF 1980 where the maxilla is disarticulated and now visible between the cranium and the preoperculum ventral to the orbit (Fig. 4A), in the juvenile Bastelberger specimen (Fig. 8) and partly in LF 1968 (Fig. 7).

Teeth of vomer and prearticular. The vomerine and prearticular teeth are smooth (without crenulations), but with a median ridge (90° to body axis; Fig. 9). This contradicts Kriwet (2000, fig. 4; 2001, fig. 4.30; 2005, fig. 35A) who described and figured the prearticular teeth of JME-SOS2343a as dentition of “Mesturus verrucosus” and he described the teeth of Mesturus based on this specimen in general: “Teeth of Mesturus have an apical indentation, which is labially displaced. The indentation is surrounded by a more or less developed crenulated wall” (Kriwet 2000, p. 451). However, JME-SOS2343a does not belong to the genus Mesturus, but to Goodichthys prettii gen. et sp. nov. (see description of this taxon below).

Tooth rows of vomer and prearticulars. Woodward (1895, p. 197) was the first who described the tooth rows of the genus “Mesturus”, but his description was based on the species leedsi, which I now describe as the new genus Aminiichthys (see below). The tooth rows of Mesturus verrucosus are best visible in LF 1980 (Fig. 9). There we can see that the vomer has five rows of teeth (Fig. 9A, B) like most Pycnodontiformes. The teeth of the median tooth row are slightly larger than the outer tooth rows, whereas the teeth of the intermediate rows (row two and four) are much smaller. The teeth in these intermediate rows are also positioned considerably deeper than the rows with the larger teeth. In LF 1980, the outer rows of teeth have at least 13 teeth. The number of prearticular tooth rows is unclear, but in LF 1980, there are at least five tooth rows visible, with the median one having the largest teeth.

Premaxillary and dentary teeth. There are two conical teeth on the premaxilla (Figs 3, 6B, 9; Suppl. material 1: fig. S1) and up to five conical teeth on the dentary (Fig. 6B).

Parietals. The number of parietals is unclear in Mesturus verrucosus, but there seems to be more than one parietal on each side of the head as in other basal Pycnodontiformes (see Aminiichthys leedsiNursall 1999a, fig. 4; PiranhamesodonKölbl-Ebert et al. 2018, Suppl. material 1: fig. S1A, B; ApomesodonEbert 2026, fig. 14). The parietals are not fully developed in the juveniles, but there are two small bones visible between the frontal, dermopterotic and the dermosupraoccipital in LF 1968 (Fig. 7). It is difficult to count the parietal bones in adults because the strong ornamentation of the bones in this area makes it difficult to distinguish bone boundaries from fractures (Figs 3, 4; Suppl. material 1: fig. S1).

Branchiostegals. There are two (Fig. 3; Suppl. material 1: fig. S1) to three (Figs 6A, 7) slender branchiostegals, of which the dorsal most is very elongated compared to other Pycnodontiformes.

Neural spines. In M. verrucosus, there are approximately 31–34 neural spines between the cranium and the caudal fin origin. In the juvenile LF 1968, the neural spines are clearly visible underneath of the incompletely developed scale rows, apart from the posteriormost in the caudal area which are disarticulated (Fig. 5; Suppl. material 1: figs S4, S5). The anteriormost three to four neural spines are slightly broader than the subsequent neural spines. As in all Pycnodontiformes, the anteriormost neural spines are separated from their neural arches (autogenous neural spines). However, in M. verrucosus, as in some other basal Pycnodontiformes (Apomesodon, Arduafrons, Brembodus, Eomesodon, Piranhamesodon, see discussion below), nearly all neural spines are separated from their arches. In LF 1968, the anteriormost 24 neural spines are separated from their neural arch, only the posteriormost ~ 9 neural spines anterior to the caudal fin origin are fused to their arches.

The neural arches are best visible in juveniles LF 1968 (Fig. 5; Suppl. material 1: figs S4, S5) and CHT 94/1 (Suppl. material 1: fig. S3). In these juveniles the neural arches, which are separated from the neural spines are paired, hourglass-shaped elements. Only the posteriormost neural arches, which are connected to their neural spines are unpaired. The neural spines in Pycnodontiformes are always unpaired.

Haemal spines. The haemal spines are not visible in adult specimens. In the juvenile (LF 1968), all haemal spines are slender and connected to the haemal arches. There are approximately 12 pleural ribs and 12 or 13 haemal spines between the post-coelomic bone and the caudal fin origin. Broadened haemal spine with ridges like in Gyrodus are absent. There are at least 10 haemal spines (including hypurals) with contact to caudal fin rays. None of the hypurals is broadened like in more advanced Pycnodontiformes.

Post-coelomic bone. In juvenile specimens between the ribs and the haemal spines, there is a relatively broad post-coelonic bone visible. However, this bone is always covered by scales and its exact outline is unknown (Bastelberger specimen (Suppl. material 1: fig. S2), LF 1968 (Fig. 5)).

Hemicentra. In the juvenile (LF 1968), ovoid hemicentra-like structures are present near the notochord anterior of the caudal fin (Suppl. material 1: fig. S5). Similar bones were described in Lambers (1991, fig. 22c) of “Gyrodus” wagneri (now Thiollierepycnodus wagneri; see Ebert 2019).

Pectoral girdle and fins. The cleithrum is large and elongated (Figs 3, 7, 8, Suppl. material 1: fig. S2). Its dorsal half is covered by the preoperculum. At least seven pectoral radials are visible (Fig. 3), as in other Pycnodontiformes. The pectoral fin is large and has at least 31 elongated lepidotrichia (Fig. 3).

Pelvic fins. The pelvic fins are small as in all Pycnodontiformes with approximately five fin rays (best visible in Fig. 5). They are located in the anterior body part; four or five scale rows posterior of the cleithrum.

In juveniles, the transition between the dorsal and ventral ridge scales of the body and the fin rays of the dorsal and anal fins is difficult to discern because the bases of the dorsal and anal fin rays are sunken into the body and, in this transition zone, the dorsal ends of the fin rays do not extend beyond the dorsal extent of the scale rows with the ridge scales (Fig. 11). The difference is most easily recognised by the fact that the ridge scales have one to five small spines at their outer end, the fin rays not having spines at the end. The smallest specimens (LF 1968 and CHT 94/1) have one relatively large spine on each ridge scale (Fig. 5; Suppl. material 1: figs S3, S5, S6), whereas the Gehrer and the Bastelberger specimens, which are a little larger, have up to five smaller spines on the ridge scales (Fig. 11; Suppl. material 1: fig. S2). In contrast, the fin rays are segmented and not so close together as the ridge scales. However, the unsegmented anterior fin rays (procurrent or ontogenetly not fully developed fin rays), are difficult to distinguish from the elongated, slender ridge scales at the end of the scale rows.

Dorsal and anal fins. In adult specimens, the dorsal and anal fins are long and low, with nearly all fin rays of the same length (“strip-like” sensuPoyato-Ariza and Wenz 2002, fig. 34A), apart from the anteriormost and posteriormost three or four rays which are slightly shorter (Figs 2, 3, 4). In juveniles, the dorsal and anal fins are comparably higher, especially in the centre or a little posterior of the centre and, therefore, more rounded than in adult specimens (Fig. 5; Suppl. material 1: fig. S3). There are around 30 (plus-minus one) dorsal pterygiophores (Suppl. material 1: table SS1), supporting 29 to 30 segmented dorsal fin rays, plus anterior to the fin rays three basal fulcra. In LF 1968, only 27 dorsal pterygiophores are visible, but there might be some missing due to disarticulation. The anal fin is somewhat shorter than the dorsal fin, but otherwise, its shape is quite similar. The anal fin is supported by 23–24 pterygiophores. In adult specimens, most rays of the dorsal and anal fin branch two times and all branched rays split near the bases of the rays. In the juvenile specimens LF 1968 and CHT 94/1, many small spines are visible on the dorsal and anal fin rays (Fig. 5; Suppl. material 1: figs S3, S5).

Caudal fin. The shape of the caudal fin, which is posteriorly convexly rounded (Figs 2, 3, 4, 5, 6, 10, Suppl. material 1: figs S2, S3) and not forked as in most Pycnodontiformes, was the main feature of Wagner (1862) for separating his new genus Mesturus from the genus Gyrodus. The posterior margin of the caudal fin is, however, homogenously rounded (Fig. 10B; Suppl. material 1: figs S2, S3). Two slight lateral bulges, as described in Wagner (1862), are absent. Comparable to other Pycnodontiformes, there is a high number of caudal fin rays. In juveniles, there are 36–38 segmented caudal fin rays, which increase in adults up to 43. Additionally, they have dorsally three to seven unsegmented fin rays or basal fulcra and ventrally two to five unsegmented fin rays or basal fulcra, with the highest number in the juveniles. In the adult specimen NHMUK PV OR 37023 (Fig. 10A), there are 38 segmented caudal fin rays of which 29 are branched. At the anterior dorsal margin of the caudal fin there are three long basal fulcra. At the anterior ventral margin, there are five basal fulcra. The rays in the middle of the fin branch at least four times. In the juvenile specimens LF 1968 (Fig. 10B) and CHT 94/1 (Suppl. material 1: fig. S3), in which the massive scales in the caudal area were not completely developed, the cleft of the notochord is visible, which separates the hypaxial from the epaxial rays. In these juveniles, there is a high number of 15 to 18 epaxial caudal fin rays or basal fulcra visible, of which at least nine are segmented. The ray segments in adult specimens are short. As in other juvenile Actinopterygii, the ray segments are comparably longer. Some rare, small and elongated fringing fulcra are visible on the dorsal and ventral lobe of the caudal fin of NHMUK PV OR 37023 (Fig. 10A). On some fin rays of the juveniles (LF 1968 and CHT 94/1), a small number of tiny spines are visible (Fig. 10B; Suppl. material 1: fig. S3).

Urodermals. In the juveniles LF 1968 (Fig. 10B), one relatively large and elongated urodermal is visible. In the Bastelberger specimen (Suppl. material 1: fig. S2) and CHT 94/1 (Suppl. material 1: fig. S3), there are two urodermals.

Squamation. In adult specimens, massive scales are present on the complete body including the caudal peduncle (imbricate scale pattern sensuNursall 1996; Figs 2, 3, 4). There are 20 (+/– one) transverse scale rows with massive scales on the body. On the caudal peduncle, there is a change in the direction of the scale rows (best visible in NHMUK PV OR 37023; Fig. 10A). The posterior border of the massive body scales is smooth (without serrations) and the surface of the scales in adult specimens is covered with granulations (Figs 2, 3, 4, Suppl. material 1: fig. S1). In juveniles, the scales of the body are not completely developed, only the anterior margin of the scales is formed (Figs 5, 6; Suppl. material 1: figs S2–S5). However, these incompletely developed scales are already arranged into incompletely developed scale rows. Relatively large spines are present on the surface and posterior margin of these incompletely developed scale rows in LF 1968 (Figs 5, 7; Suppl. material 1: figs S4, S5).

Between the ventral part of the cleithrum and the jaws, there are additional smaller, more rounded scales. Similar rounded scale like elements, but in lower number, could be found all over the cranium.

Most characteristic of this genus is the bifurcating of scale rows of the body towards the whole of the dorsal margin and towards the caudal half of the ventral margin (Woodward 1895, pl. 15; Nursall 1999a, fig. 2; Figs 3, 4, 5, 6; Suppl. material 1: fig. S2). This feature is, apart from Arduafrons prominoris, unknown in other Pycnodontiformes including other Mesturidae. This bifurcating of scale rows is already present in juveniles (Figs 5, 6; Suppl. material 1: figs S2–S5).

As in all Mesturidae, the scales within the same scale row of the trunk are connected in a jagged suture (see drawings in Woodward 1895, pl. 15; Nursall 1999a, fig. 2; Fig. 3B). Corresponding to the 23 scale rows of the central body part anterior of the dorsal fin origin, which bifurcate dorsally, there are approximately 46 dorsal ridge scales between the cranium and the dorsal fin origin. In the less developed juveniles (LF 1968and CHT 94/1), the dorsal ridge scales and ventral keel scales are developed as spine-like elements like the incomplete scales of the body (Fig. 5). In somewhat further developed juveniles (Gehrer specimen, Bastelberger specimen; Fig. 6; Suppl. material 1: fig. S2), the dorsal and ventralmost three or four scales of one scale row, including the ridge scales and the dorsal lateral line scale begin to become broader and look similar to the scales in adults. The scale row of the main lateral line also develops further at this stage and the thickened granulations on the scales of the main lateral line, known in adult specimens, become visible (Fig. 6; Suppl. material 1: fig. S2).

Between cloaca and anal fin origin, there are approximately 20 scale rows with at least 20 ventral keel scales (Fig. 11C), which is like the condition in the genus Gyrodus. The number of ventral keel scales between the cloaca and the cleithrum is much lower. However, there is no clear boundary here, as these small scales extend across the cheek region to the jaws (Fig. 18A).

The cloacal area in juveniles is broad with many small scales (Fig. 11C), but in adults, the cloacal area is hardly visible (Fig. 4, Suppl. material 1: fig. S1). Poyato-Ariza and Wenz (2002, p. 202) describe this problem as “the cloaca is apparently absent only in all observed specimens and figures of Mesturus, in which we have seen no modified scales in this area”.

Scales between fin rays of the dorsal and anal fin were already figured in Nursall (1999b, fig. 13) for the adult specimen NHMUK PV OR 37023. Particularly on the anal fin of the juvenile fish LF 1968, it became clear that these scales are not extensions of the scale rows of the body, as these scales are rounder and arranged differently from the more elongated scales of the body (Fig. 5; Suppl. material 1: fig. S5).

Sensory lines. The main lateral line of the body is visible on its entire length in the area of the notochord from the cranium to the caudal fin. In the anterior body part of the adult specimen NHMUK PV OR 37023, the surface of the lateral line scales is characterised by irregular tubercles that are significantly larger than those of the other body scales (Fig. 3). This character was already figured in Woodward (1895, pl. 15) and described as diagnostic for the species in Nursall (1999a, p. 157). In the posterior body part, the main lateral line is only visible as a thin line that is sunk into the scales. In some of the juvenile specimens, the scale row of the main lateral line is already beginning to differentiate and the thickened granulations on the scales of the main lateral line, known in adult specimens, become visible (Fig. 6; Suppl. material 1: fig. S2).

The dorsal lateral line is only partially visible in a few juveniles, through already thickened scales that have a sunken line in the middle (Fig. 6; Suppl. material 1: fig. S2).

The sensory lines of the cranium in M. verrucosus are unknown due to the thick granulations of the cranial bones.

As a lasting memorial to of Jina Mahsa Amini, a 22-year-old Kurdish-Iranian woman who died on 16 September 2022 in a Teheran hospital due to physical violence she suffered while in morality police custody for an alleged violation of the Iranian Hijab law: Woman, Life, Freedom! (https://en.wikipedia.org/wiki/Jina_Amini accessed on 27 January 2026.)

As for type and only species.

This taxon was transferred to a new genus primarily based on tooth ornamentation, but also on differences in scale pattern (absence of bifurcation) and scale ornamentation. Due to the state of preservation of the specimens, many characteristics typical for Mesturus verrucosus are unknown in the new genus, especially the shape of the anal, dorsal and caudal fins.

NHMUK PV P.8382 (Figs 12A–D, 14A–C, 15A–C).

Near Peterborough, Cambridgeshire, England.

Lower Oxford Clay, Middle Jurassic, Callovian.

The holotype is the specimen in Woodward (1896, pl. 1), since Woodward (1896, p. 12) fixed this specimen as type “The fossil no. 1 (Leeds Catalogue) must be regarded as the type specimen”. There has some confusion about the identification of this specimen. The holotype is not NHMUK PV P.8385 as erroneously mentioned in Martill et al. (1998) nor is it NHMUK PV P.6834 as mentioned in Nursall (1999a), Kriwet (2001), Poyato-Ariza and Wenz (2002) and Bernard and Smith (2016). In Woodward’s time, only NHMUK PV P.6834 went to the NHMUK collection, all other specimens described in Woodward (1895, 1896), including the holotype, were still in the Alfred N. Leeds collection and went to the NHMUK much later. Woodward (1896, pl. 1) only figured the cranium with remnants of the anterior scale rows (Fig. 12A–D), but from his description of the scale rows of his specimen no. 1 (the holotype), it became clear that he also has studied the additional fragment with the median body part (see Fig. 12E).

From the Oxford Clay near Peterborough, England: CAMSM J27370 from Whittlesea; CAMSM J27370 (Fig. 13), 27371 (Suppl. material 1: fig. S14), 27372, 27374, 27375; GPIT-PV-118313; NHMUK PV P. 8383a (Fig. 16D), 8384, 8385 (Fig. 16A, C). Photos to the NHMUK specimens can be viewed under https://data.nhm.ac.uk/

(amended from Woodward 1895, 1896; Nursall 1999a). Large, Mesturidae, with the following unique combination of characters: teeth in vomer and prearticular exhibit a shallow apical indentation, with a granulated margin; at least the anteriormost 15 scale rows do not bifurcate dorsally in contrast to M. verrucosus (the posterior scale rows are unknown); with fewer and larger granules on the scales and cranial bones than Mesturus verrucosus; scales of main lateral line without enlarged tubercles.

Remarks. The species Aminiichthys leedsi (Woodward, 1895) gen. nov. was described in detail by Woodward (1895, 1896) and Nursall (1999a). Therefore, I will only describe new insights regarding a few characteristics here. The descriptions in the above-mentioned articles are based on specimens from the collection of Alfred N. Leeds, which are now largely in the collection of the NHMUK. In the present article, I show, for the first time, photos of the holotype (NUMUK PV P.8382; Figs 12, 14, 15), of which even more scale rows are preserved as drawn in Woodward (1896, pl. 1). In addition, I examined two further specimens from the collection in the Sedgwick Museum of Earth Sciences, University of Cambridge, U.K., of which the anterior half of the body is largely preserved (Fig. 13; Suppl. material 1: fig. S6) and I figure a prearticular from the collection in Tübingen (Fig. 16B).

Fossils from the Oxford Clay are threatened by pyrite oxidation. Many articulated fossils already show cracks (Figs 12, 13; Suppl. material 1: fig. S6) or are in the process of disintegrating.

General morphology and size. The known fragments of Aminiichthys leedsi (Woodward, 1895) gen. nov. suggest a similar body shape and maximum size to Mesturus verrucosus. Reaching sizes of up to 50 cm, Aminiichthys leedsi was probably the stratigraphically oldest representative of the Pycnodontiformes which have achieved such dimensions. In general, this taxon is amongst the largest known Pycnodontiformes. Juvenile specimens of A. leedsi are unknown.

Dentition. Woodward (1895, p. 197) was the first who described the tooth rows of this taxon. The arrangement and ornamentation of the teeth in the vomer and prearticular is described in detail in Woodward (1896), but since the ornamentation is important to distinguish the genera of Mesturidae and basal Pycnodontiformes in general, I will describe and figure them here again (Fig. 16). Woodward (1896, p. 9) writes “All these tritoral teeth in both jaws [vomer and prearticular] … exhibit a shallow apical indentation, with a crimped margin, very rarely also with a slight median tubercle. The shape of the indentation varies with that of the tooth, and the hinder portion of its crimped border is not infrequently wanting”. The “crimped margin” is here and in most other more recent articles about Pycnodontiformes mentioned as granulated margin. Presumably, the posterior margin of the larger teeth is often worn down in larger specimens.

SensuWoodward (1896), the vomer (Fig. 16A) and the prearticular (Fig. 16C) on his plate 2 belong to one specimen (originally Leeds Catalogue 24, now NHMUK PV P.8385).

Fringing fulcra. Woodward (1896, p. 11) mentioned fringing fulcra on a fragment of the caudal fin of his specimen no. 2 (today NHMUK PV P.8383; Suppl. material 1: fig. S7).

Scales. The known body scales are large, rectangular and massive, with large granules on the surface (Figs 12, 13; Suppl. material 1: fig. S6). These granules are about twice the size of those in Mesturus verrucosus and, consequently, there are significantly fewer of them per scale. As mentioned in Nursall (1999a), one of the diagnostic features of the taxon is the absence of significantly larger granules on the lateral line scales in A. leedsi, which are present in M. verrucosus. Another difference to M. verrucosus is the absence of bifurcation of scale rows. At least the anteriormost 15 scale rows do not bifurcate in A. leedsi (the posterior scale rows are unknown). As in all Mesturidae, A. leedsi has jagged sutural connections between the trunk scales (Woodward 1896, pl. 1, fig. 1; pl. 3, fig. 1; Figs 12, 13; Suppl. material 1: fig. S6).

In memory of Renée Good, who was shot dead by an ICE officer on 7 January 2026, in Minneapolis, Minnesota. She had tried to stand by her neighbours against the ICE operation (https://en.wikipedia.org/wiki/Renée_Good accessed on 27 January 2026).

As for type and only species.

JME-SOS2343 (Fig. 17A, B).

In memory of Alex Jeffrey Pretti, who was murdered by Federal Immigration and Customs Enforcement (ICE) officers on 24 January 2026, in Minneapolis, Minnesota (https://en.wikipedia.org/wiki/Alex_Pretti, accessed 27 January 2026).

Wintershof, Solnhofen Archipelago, Bavaria, Germany.

Upper Jurassic, Lower Tithonian (Hybonotum Zone, Ridense Subzone, eigeltingense β Horizon).

(all from the Upper Jurassic of the Eichstätt Basin, Solnhofen Archipelago, Bavaria, Germany). Collection Schäfer (former coll. Kümpel; Arratia and Schultze 2015, fig. 759; Suppl. material 1: fig. S8); CHT 85/114 (former coll. Kraus; Frickhinger 1991 figure on p. 398 and Frickhinger 1994, fig. 453; Suppl. material 1: fig. S9); JME-SOS2366 (Fig. 18A); SMF P9338 (Fig. 18B).

Medium-sized, basal Pycnodontiformes reaching 29 cm total length (25.5 cm SL), with two unique features (indicated with an asterisk *): caudal peduncle large and caudal fin origin much posterior to posteriormost dorsal and anal fin rays* (longest caudal peduncle covered with massive scales in all Pycnodontiformes); large, horizontally elongated scales ventral of the cleithrum*, same elongated scales in the throat area, but smaller. In addition, the species is characterised by the following unique combination of features: body depth to standard length 52–57%; maxilla ornamented; vomerine and prearticular teeth granulated exhibit an apical indentation, with a strong granulated margin; dorsal and anal fins elongated with approximately 19–21 anal and 19–22 dorsal fin rays, but with consistently short fin rays which branch only two times; caudal fin filled with an almost straight posterior border; dermal skull elements irregularly arranged including a variable number of marginal bones on the anteroventral part of the frontals to the premaxilla; scale rows of the body do not bifurcate, but change direction and become smaller in front of the dorsal and anal fin; scales of the body covered with fine granulations similar to Mesturus verrucosus, but scales of main lateral line without markedly enlarged tubercles.

General morphology and size. Goodichthys prettii gen. et sp. nov. is a medium size Pycnodontiformes, which is known from small specimens of 13 cm total length (TL) up to 29 cm (TL) (for measurements of specimens, see Suppl. material 1: table SS1). The body shape is ovoid with a maximum body depth between 52–57% of standard length (SL).

Skull roof and ethmoidal region. The bones of the skull are not well preserved in any specimen. The surface of nearly all head bones is covered with fine, unordered granulations, only on the preoperculum, these granulations are ordered to ridges. The ethmoidal region is covered with irregularly arranged dermal skull elements (Fig. 18B; Suppl. material 1: fig. S9). The eye is comparatively large and surrounded by a sclerotic ring (Figs 17, 18A; Suppl. material 1: fig. S9).

Opercular series. The preoperculum is large, pear-shaped and is three times the size of the operculum. The operculum is reduced in size as in all Pycnodontidae. The anterior border of the operculum to the preoperculum is straight and the posterior border is bow-shaped. Dorsally, the operculum covers a small part of the supracleithrum. A small portion of the hyomandibular is visible dorsally to the preoperculum, called the dermohyomandibular by Nursall (1996).

Jaws and dentition. Little is known of the jaws and dentition of this new taxon. The premaxilla and dentary dentition are best visible in CHT 94/1 (Suppl. material 1: fig. S9). In this specimen, there are two premaxillary teeth, of which the anterior tooth has double the width of the posterior tooth. The dentary of this specimen shows three teeth of which the anterior one has double the length and width of the posterior two. The vomer and the prearticular dentition are best visible in the holotype (JME-SOS2343; Fig. 19). The left side of the vomer is visible in the holotype in lateral view with at least 16 teeth. The outer edge of these teeth has a wavy line. The prearticular dentition is most visible. The prearticular teeth are arranged in at least five longitudinal rows. The dentition of this specimen (JME-SOS2343) was already described and figured by Kriwet (2000, fig. 4; 2001, fig. 4.30; 2005, fig. 35A) under the species name “Mesturus verrucosus”. Kriwet (2001, p. 262): “Tritorial teeth with apical indent which is somewhat anteriorly disposed. Apical indent surrounded by crimped margins when unworn”. Additionally, to this crimped margin or “crenulated wall” (Kriwet 2000, p. 451), there are further granulated lines that run in a star shape from the base of the tooth to the previously mentioned wall.

Axial skeleton. The axial skeleton is difficult to see through the scales in all specimens; therefore, only a few details are provided here. The arcocentra do not surround the notochord, not even in the caudal area. In the holotype, the number of arcocentra and corresponding neural spines (excluding those supporting caudal fin rays) is 30 or 31 (Fig. 17; for comparison of specimens, see Suppl. material 1: table SS1).

Pectoral girdle and fins. The cleithrum is large with its dorsal part covered by the preoperculum. The pectoral fin (best visible in the Schäfer specimen, Suppl. material 1: fig. S15B) is large and fan-shaped with at least 21 elongated fin rays plus one basal fulcrum. It is based on at least seven pectoral radials as in other Pycnodontiformes.

Pelvic fins. The pelvic fins are small as in all Pycnodontiformes, but hardly visible in any of the specimens. The pelvic fins are situated very anterior in the body, approximately ventral to the position of the pectoral fin origin or slightly anterior.

Dorsal and anal fin. The dorsal and anal fins are elongated with approximately 19–21 anal and 19–22 dorsal fin rays. However, these fins have fewer fin rays than Mesturus verrucosus and the number of dorsal (~ 20) and anal (~ 21) pterygiophores is also lower. The fin rays are short on their entire length, have a relatively large distance to each other and branch a maximum of two times. The dorsal and ventral boundaries of these fins are almost straight (“strip-like” sensuPoyato-Ariza and Wenz 2002, fig. 34A) even in smaller specimens.

Caudal peduncle and fin. The caudal peduncle is long, even longer than in Mesturus verrucosus and the caudal fin does not “nearly surrounding the short caudal pedicle” as described by Woodward (1895, p. 218) for the genus Mesturus. This is the longest caudal peduncle covered with massive scales in all Pycnodontiformes.

The caudal skeleton is not visible due to the covering with thick scales.

The caudal fin is large and fan-shaped with a nearly straight posterior margin (Figs 17, 18; Suppl. material 1: figs S8, S9). There are 35–36 segmented caudal fin rays. Apart from the dorsal- and ventralmost, the rays branch three to four times. At the anterior dorsal margin of the caudal fin, there are two or three basal fulcra. At the anterior ventral margin, there are one or two basal fulcra. Fringing fulcra are absent on all fins.

Squamation. Massive body scales are present on the whole body and on the bases of the fin rays. There are 31–34 scale rows of complete body scales between the operculum and the caudal fin origin and 18–20 scale rows to the dorsal fin origin. The posterior border of the massive body scales is smooth and the surface of the scales is covered with granulations (Figs 17, 18; Suppl. material 1: figs S8, S9) comparable to that in Mesturus verrucosus. The scale rows of the body do not bifurcate, but change direction and become smaller in front of the dorsal and anal fin. Scales of main lateral line without markedly enlarged tubercles. There are some large, horizontally elongated scales ventral of the cleithrum (Fig. 20B; Suppl. material 1: fig. S9), which are unique for Pycnodontiformes. Similar elongated scales are present in the throat area, but in this area, the scales are generally smaller (Fig. 20B).

There is always one dorsal ridge scale at the dorsal end of each scale row in the anteriordorsal body part in front of the dorsal fin. The anteriormost three dorsal ridge scales are slightly larger than the posterior ones. The dorsal ridge scales are dorsally bordered with up to four small spines. These spines are all roughly the same size and are not in contact to each other. The lateral line canal is not clearly visible due to the ornamentation of the scales. There are no specifically-shaped ventral keel scales in any of the specimens. As in adult specimens of Mesturus verrucosus, modified cloacal scales are apparently absent.

Specimen of Mesturidae also occur in the Kimmeridgian of Nusplingen, Baden-Württemberg, Germany. At least one fragment (SMNS-P-97055/4) with remnants of seven or eight scale rows connected by jagged sutures can be clearly assigned to the Mesturidae.