Taxonomic status of the caturid genera (Halecomorphi, Caturidae) and their Late Jurassic species

2.1. Abbreviations

Institutional Abbreviations. AMNH, American Museum of Natural History, New York, USA; CAM SM, Sedgwick Museum, Cambridge University, Cambridge, United Kingdom; JME, Jura-Museum Eichstätt, Germany; LDGSL, Deposited Series, Geological Society Archive Catalogue, Geological Society, London, United Kingdom; LMU, Ludwig Maximilians University, Munich, Germany; MB.f, Museum für Naturkunde, Berlin, Germany; MCZ, Museum of Comparative Zoology (Harvard University) Cambridge, Massachusetts, USA; MGB, Museo de Geología de Barcelona, Barcelona, Spain; MHNL, Muséum d'Histoire Naturelle de Lyon, France; MOZ, Museo Provincial Dr Prof. Juan Augusto Olsacher, Zapala, Neuquén, Argentina; NMNH, National Museum of Natural History (Smithsonian Institution), Washington, DC, USA; MPCA, Museo Provincial ‘Carlos Ameghino’, Cipolletti city, Río Negro province, Argentina; MRAC, Musée Royal de l'Afrique Centrale, Tervuren, Belgium; NHMUK, Natural History Museum, London, United Kingdom; NMP, National Museum Prague, Department of Palaeontology, Czech Republic; OUMNH, Oxford University Museum of Natural History, United Kingdom; SMNS, Staatliches Museum für Naturkunde Stuttgart, Germany; SNSB-BSPG, Staatliche Naturwissenschaftliche Sammlungen Bayerns–Bayerische Staatsammlung für Paläontologie und Geologie, Munich, Germany; TLM, Sammlungs- und Forschungszentrum der Tiroler Landesmuseen, Hall in Tirol, Austria; TM, Teylers Museum, Haarlem, The Netherlands.

3.1. Caturoidea Owen, 1860 [19] sensu Grande & Bemis [13]

The superfamily Caturoidea is apomorphy-based defined by the following features: (1) the presence of sharply carinate acrodin tooth caps on the larger jaw teeth; (2) the presence of an extremely slender rod-like maxilla; (3) a relatively high number of branchiostegal rays (22 or more on each side); (4) shape of haemal spines broadly spatulate in the transverse plane; (5) the preural haemal and neural spines near the caudal peduncle region are strongly inclined to a nearly horizontal orientation [13].

3.1.1. Strobilodus Wagner, 1851 [38]

Type species—Strobilodus giganteus Wagner, 1851 [38], with neotype SNSB-BSPG 1953 I 579 (figure 1).

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Discussion—The genus Strobilodus was erected by Wagner [38] for an imperfectly preserved but very distinct fish from the Upper Jurassic (upper Kimmeridgian [39]) lithographic limestones of Kelheim (most probably Kapfelberg), Germany, in the Munich palaeontological collection, which he named Strobilodus giganteus. Wagner's description of the species is rather extensive (electronic supplementary material, File), and he mainly distinguishes this taxon based on the very powerful dentition consisting of a series of strongly built cone-shaped teeth, which decrease in size towards the posterior end of the maxilla. He further described the lower jaw as narrow. Wagner accompanied his description with an illustration of the skull, pelvic bone and some disarticulated scales of the original specimen [38, pl. 2]. The type specimen is lost, but the description and illustration warrant the identification of the species which is well represented by specimen SNSB-BSPG 1953 I 579 from the locality of Painten close to Kelheim, Germany.

The very distinct shape of the maxilla (distinctly broader than in Caturus or Amblysemius), the relatively narrow and anteriorly tapering dentary, and the powerful conical teeth undoubtedly distinguish Strobilodus from Caturus. The marginal cutting teeth of Caturus have laterally compressed and sharply carinate acrodin caps. The marginal jaw bones of Strobilodus are garnished with strong fangs with conical caps. However, and despite recognizing the morphological differences, Woodward [40] placed the two genera under synonymy and the species has been treated as Caturus giganteus since then (e.g. [23,28]). Here, we not only revalidate Strobilodus giganteus as a distinct genus, but we also indicate other species that might also represent this very distinct taxon (§4) [32,33,35].

Wagner's [38] description and illustration of Strobilodus giganteus, as well as the proposed neotype, diverge from the apomorphy based diagnosis of Caturoidea on the morphology of the teeth and maxilla (features 1 and 2). The branchiostegal rays (character 3) are not preserved, but the haemal spines are transversally compressed, strongly inclined and tightly packed as indicated in characters 4 and 5. A thorough revision of the taxon and the study of its phylogenetic relationships are necessary to clarify its potential sister group relationship with other caturids. Pending such a study, Strobilodus is here removed from the Caturidae sensu Grande & Bemis [13] and it is tentatively placed in Caturoidea incertae sedis.

3.2. Caturidae Owen, 1860 [19] sensu Grande & Bemis [13]

3.2.1. Caturus Agassiz, 1834 [40]

Type species—Caturus furcatus (Agassiz, 1833) [41] with holotype NMP Uc9 (counterpart Uc83) (figure 2).

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Discussion—The name Caturus Agassiz, 1834 [42] was introduced as a nomen novum to replace Uraeus Agassiz, 1832 [43] because it was preoccupied by Uraeus Wagler, 1830 [44], which is a subgenus of the cobras Naja [45]. The latter name was erected by Agassiz, including two nominal species Uraeus pachyurus and Uraeus gracilis. None of these nominal species was accompanied with an illustration or sufficient description, and none of them was designated as the type species of the genus. Many years later, Woodward [40] presented Caturus furcatus (Agassiz, 1833) [41] as the type species of the genus, but this designation is incorrect because the type species of a genus must be chosen among the originally included taxa (ICZN Art. 67.2).

Of the two species originally included in Uraeus, U. pachyurus is not an available name because it is not accompanied with a description, definition or indication (ICZN Art. 12.1). The simple references given by Agassiz for this species are not sufficient to constitute an indication (ICZN Arts. 12.2 and 12.3). Agassiz [43, p. 142] only wrote: ‘Von diesem Genus und zwar vom Solnhofer Uraeus pachyurus ist das schönste Exemplar, das ich je gesehen, in der Bronn'schen Sammlung in Heidelberg’ [Of this genus, and specifically of the Solnhofen Uraeus pachyurus, the most beautiful specimen I have ever seen is in the Bronn collection in Heidelberg]. Although the nominal species takes authorship and date Uraeus pachyurus Agassiz, 1833 [41] (figure 3a,b; see below), it is excluded from the taxa originally included in Uraeus Agassiz, 1832 [43].

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Consequently, the type species of Uraeus Agassiz, 1832 [43] is U. gracilis by monotypy (ICZN Arts. 67.2). The morphological features indicated for Uraeus gracilis are not sufficient to distinguish a species: ‘U. gracilis AG. Sehr schlank, und bedeutend groß, ziemlich großschuppig’ [43, p. 142] [U. gracilis AG. Very slender, and significantly large, rather large-scaled]. In 1833, Agassiz [41] moved his U. gracilis to the new genus Pachycormus, including also P. furcatus and P. macropterus, adding the provenance of the species in the Lower Jurassic (Lias) of Baden-Württemberg, Germany. Although it has not been possible to locate the type specimen, there exists an unpublished illustration (LDGSL/614/2/88) possibly representing the fossil studied by Agassiz [41,43]. This artwork performed by C. Weber between 1831 and 1834 (v 3C) shows a fish labelled ‘Pachycormus gracilis, Uraeus gracilis', indicated ‘from Stuttgart’, but it is unclear if this is a reference to the locality or the collection. However, the reference probably refers to a natural history collection in Stuttgart, a predecessor of the Natural History Museum in Stuttgart (SMNS), because the Lower Jurassic outcrops of Baden-Württemberg do not reach the city of Stuttgart. The fossil represented in LDGSL/614/2/88 is very incomplete preserving only the middle body of a pachycormid-like fish without the skull and most fins, with only a portion of the dorsal fin preserved. The drawing was stored in a folder labelled ‘Pachycormus and Sauropsis' (both Pachycormidae). Based on the illustration or the brief original description, it is not possible to identify the fish at a lower taxonomic level, and it has been impossible to find the specimen in the SMNS collections (E. Maxwell 2022, personal communication). Therefore, although the brief and uninformative characterization of this species is acceptable as a definition in the light of ICZN Art. 12.1, the name Uraeus gracilis represents a nomen dubium.

The discovery of the overseen type species of Uraeus Agassiz, 1832 [43] now threatens the stability of the long-accepted names of Caturus and Pachycormus in their conventional meaning. In 1833, Agassiz [41] erected the name Pachycormus, including three species: P. furcatus Agassiz, 1833 [41], P. macropterus (Blainville, 1818) [46] and P. gracilis (= Uraeus gracilis Agassiz, 1832 [43]). Therefore, Pachycormus is an objective junior synonym of Uraeus. In 1834, Agassiz [42] replaced his Uraeus with the name Caturus and, thus, the latter is the objective senior synonym of Pachycormus. All these generic names have the same type species Uraeus gracilis Agassiz, 1832 [43], which is a nomen dubium. To preserve the stability of the well-established names Pachycormus, with type species P. macropterus, and Caturus, with type species C. furcatus, an application to the International Commission on Zoological Nomenclature will be submitted to the Bulletin of Zoological Nomenclature. Pending the resolution of this case, we keep the broadly accepted designation of Caturus furcatus as the genotype [40].

3.2.2. Amblysemius Agassiz, 1844 [46]

Type species—Amblysemius bellicianus Thiollière, 1851 [47], with holotype MHNL20015164 (figure 4).

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Discussion—The generic name Amblysemius was erected by Agassiz in 1844, recognizing its similitude with Caturus but providing several features distinguishing the new nominal taxon from the latter. These features constitute a description or definition in the sense of ICZN Art. 12, thus making the name Amblysemius Agassiz, 1844 [49] available. However, the content of the genus is unknown. In the nomenclatural act of erecting the generic name Amblysemius, Agassiz [49, vol. 2, part 2, p. 119] did not name or indicate a species representing the content of the genus. Later, though with the same publication date, Agassiz [49, vol. 2, part 2, p. 165] listed ‘Amblysemius gracilis.— Oolite de Northampton’. Without description, definition or indication and, thus, failing to conform to ICZN Art. 12, Amblysemius gracilis Agassiz, 1844 [49] is a nomen nudum (unavailable name).

Resembling the case of the holotype of Uraeus gracilis, there exists an unpublished artwork of a specimen labelled Amblysemius gracilis (LDGSL/614/2/103a). The illustration was performed by Charles Weber for Louis Agassiz's ‘Recherches sur les Poissons Fossiles' between 1833 and 1843/1844, but it is not accompanied by any information on the provenance of the fossil and there is no evidence that it could be the fish from the Oolite of Northampton examined by Agassiz. Although Amblysemius stayed bound to it, the nominal taxon Amblysemius gracilis was never described or figured remaining obscure [50,51]. Woodward [40, p. 350] wrote: ‘Nothing is known of the so-called Amblysemius gracilis (…) from the Oolite of Northampton, said to be closely related to Caturus (…)’.

In 1851 Thiollière [47] erected the specific name Amblysemius bellicianus for a fish from the Upper Jurassic (upper Kimmeridgian [48]) lithographic limestones of Cerin, France (original spelling by Thiollière in the same publication corrected ‘bellovacinus’ on page 38 to ‘bellicianus’ in a footnote on page 58 and in a section ‘ERRATA’ on page 76). The name A. bellicianus Thiollière, 1851 [47] is accompanied with a description and, thus, it is available (ICZN Art. 12). Although there is no indication or illustration of a type specimen, the specimen MHNL20015164 (figure 4) belonging to the collection Thiollière in the Museum de Lyon and labelled ‘Amblysemius bellicianus', with the specific epithet corrected and the year 1850 on the label, is most probably the fossil on which Thiollière based this species. Therefore, in agreement with ICZN Arts. 72.2 and 72.4.1 specimen MHNL20015164 is here fixed as the holotype of Amblysemius bellicianus Thiollière, 1851 [47]. MHNL20015159 is the counterpart of MHNL20015164. It is mainly a cranium which was prepared with acid.

Since the species first included in Amblysemius, A. gracilis Agassiz, 1844 [49], is a nomen nudum, A. bellicianus Thiollière, 1851 [47] is the first available name expressly included in Amblysemius Agassiz, 1844 [49], and, according to ICZN Art. 67.2.2, it must be accepted as the type species of the genus.

It is worth noting that there has been tremendous confusion about the definition of Amblysemius Agassiz, 1844. Saint-Seine [52] questioned the validity of A. gracilis Agassiz, 1844 [49] and considered ‘A.’ bellicianus Thiollière, 1851 [47] as a species of Caturus. However, Saint-Seine's [52] description of Caturus bellicianus is mainly based on the specimen MHNL20015172, which he erroneously took for the holotype. Thiollière described and illustrated MHNL20015172 under the name ‘Caturus elongatus Agassiz’ [47, pp. 34–35; 53, p. 18, pl. VII, fig. 2].

Lambers [23,28] is very confusing about type species and type specimens. To begin with, he indicates ‘Amblysemius gracilis (Agassiz 1833)’ as the type species of the genus Amblysemius [23, p. 136] instead of Amblysemius gracilis Agassiz, 1844 [49], apparently mixing up the name with Uraeus gracilis Agassiz, 1832 [43], which is a different nominal taxon (see above). Lambers later notes ‘A. pachyurus (Agassiz, 1832)’ from the Solnhofen Archipelago, Germany, as the type species of Amblysemius in the systematic palaeontology section, but otherwise indicates A. gracilis as the type of the genus elsewhere in the text [28, pp. 91, 97]. Although he recognizes ‘A. pachyurus (Agassiz, 1832)’ and ‘A. bellicianus Thiollière, 1851’ as valid taxa, he did not examine the corresponding type material. He acknowledges not knowing the type specimen of Caturus pachyurus, which he considered lost, and his taxonomic conclusions on ‘A. pachyurus’ are based on the holotype of Caturus granulatus Münster, 1842 (SNSB-BSPG AS VII 1139) from Kelheim, Bavaria, Germany, arguing its overall similarity with specimens labelled C. pachyurus (SNSB-BSPG AS I 1249 from Eichstätt and NHMUK PV P 44900 from Solnhofen, both Bavaria, Germany). On the other hand, Lambers [23,28] based his diagnosis and description of his ‘A. bellicianus’ on the specimen that Thiollière referred to Caturus elongatus, MHNL20015172 from Cerin, France, which was erroneously taken as the holotype of ‘A.’ bellicianus by Saint-Seine [52], and the then still unstudied specimen SNSB-BSPG 1969 XVII 50 from Zandt, Bavaria, Germany.

4.1. Uraeus pachyurus Agassiz, 1832 [42]

Nomen nudum (see §3.2.1).

4.2. Uraeus nuchalis Agassiz, 1833 [41]

The type specimen is unknown, and the original and only known description is insufficient to validate the taxon: ‘U. nuchalis. Nacken wulstig mit grösseren Schuppen; Körper gegen den Schwanz schmäler werdend. Solenhofen’ [41, 477] [U. nuchalis. Nape bulging with larger scales; body narrowing towards the tail. Solnhofen].

The nominal taxon has been considered a junior synonym of Caturus furcatus [40,49,54], but it is not possible to either confirm or refute such hypothesis and the taxon is here regarded as a nomen dubium.

4.3. Uraeus pachyurus Agassiz, 1833 [41]

The original description is not sufficient to validate the taxon: ‘U. pachyusus. Schwanz dick; Körper in gleicher Flucht; Solenhofen’ [41, 477] (specific epithet misspelled) [U. pachyurus. Tail thick; body in equal alignment; Solnhofen]. An unpublished illustration labelled Uraeus pachyurus of a complete specimen from Solnhofen, Germany, which was part of the Bronn Collection in Heidelberg, has been found in the Geological Society Archive Catalogue LDGSL/614/2/79 (figure 3a). Although it was finally not included, the illustration by Joseph Dinkel was made for Agassiz's ‘Recherches sur les Poissons Fossiles'. Furthermore, the specimen has been located in the Museum of Comparative Zoology with collection number MCZ VPF-6262 (figure 3b), and additional information accompanying the specimen supports the hypothesis that this is most probably the fossil meant to represent U. pachyurus by Agassiz [43]. Therefore, according to the Arts. 72.4.1.1 and 73.1.2 of the Code, specimen MCZ VPF-6262 is the holotype of Uraeus pachyurus Agassiz, 1833.

The nominal taxon Caturus (Uraeus) pachyurus has been considered as a distinct species of Caturus by Wagner [54], Woodward [40] and Heineke [55], or as the type species of Amblysemius by Lambers [28]. However, none of those authors examined the type specimen, which is complete but rather poorly preserved. Because of the deficiency of the original description and the absence of diagnostic features in the holotype MCZ VPF-6262, this nominal taxon is considered a nomen dubium.

4.4. Uraeus macrocephalus Agassiz, 1833 [41]

Holotype SNSB-BSPG AS I 1134 from Solnhofen, Germany. The species was first referred to the genus Pholidophorus and split in two taxa, Ph. macrocephalus and Ph. uraeoides [41], and later distinguished as a new taxon Siemensichthys macrocephalus [56], including Ph. uraeoides as a junior synonym.

4.5. Uraeus microlepidotus Agassiz, 1833 [41]

Holotype SNSB-BSPG AS V 11a,b, from Eichstätt (holotype according to Lambers [57]). The species was referred to Eugnathus by Agassiz [58] and is currently accepted as ‘Furo’ microlepidotes [57,59,60].

4.6. Uraeus macrurus Agassiz, 1833 [41]

The original and only available description is very unsatisfactory: ‘U. macrurus. Klein mit verhält. sehr grossem tiefgabeligem Schwanz’ [41, 477] [U. macrurus. Small with a proportionally very large deeply forked tail]. Three unpublished illustrations of specimens labelled ‘Uraeus macrurus’, two by Charles Weber in 1831 (LDGSL/614/2/72 and LDGSL/614/2/73) and one by Joseph Dinkel in 1834 (LDGSL /614/2/71; figure 5a), might represent the type specimens. The first two of these specimens from Solnhofen were in the Paleontological Museum in Munich and were probably destroyed during WWII. The third specimen from Kelheim (most probably Kapfelberg), Germany has been located in Prague with collection number NMP Uc74 (figure 5b). Therefore, according to the Arts. 72.4.1.1 and 74.7 of the Code, specimen NMP Uc74 is hereby designated lectotype of Uraeus macrurus Agassiz, 1833.

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The species Caturus (Uraeus) macrurus has been considered as a junior synonym of Caturus furcatus [23,28,40]. The lectotype is significantly smaller than the holotype of Caturus furcatus and shows some morphological differences that might be due to ontogenetic variation. However, by examining the type material we have not yet been able to confirm either the synonymy or the validity of the taxon. Detailed study of this material will clarify the potential validity of C. macrurus Agassiz, 1833.

4.7. Caturus furcatus (Agassiz, 1833) [41]

Original name Pachycormus furcatus. Holotype NMP Uc9 (counterpart Uc83) (figure 2), from the Upper Jurassic (upper Kimmeridgian [39]) lithographic limestones of Kelheim (most probably Kapfelberg), Germany. The species was transferred to Caturus by Agassiz [62]. As explained above (§3.2.1), for the time being it remains the type species of the genus.

4.8. Caturus elongatus Agassiz, 1834 [62]

The nominal species is accompanied with a brief description: ‘Caturus elongatus Agass. (Uræus elongatus dans les collections que j'ai étiquetées.) Corps plus élancé que dans les autres espèces du genre. C. très-grande, très-fourchue. A. très -petite, étroite et courte. D. large, ayant un grand nombre de petits rayons dans son bord antérieur. Solenhofen’ [62, p. 13] [Caturus elongatus Agass. (Uræus elongatus in the collections I have labelled.) Body more slender than in the other species of the genus. Caudal fin very large, very forked. Anal fin very small, narrow and short. Dorsal fin broad, having a large number of small rays in its anterior margin. Solenhofen]. A watercolour study by Sixtus Heinrich Jarwart in 1837 (LDGSL/614/2/67) of a complete specimen from Solnhofen, Germany, in the collection of Georg Graf von Münster which became part of the collection of the SNSB-BSPG, shows a very imperfectly preserved fish that matches the specimen described as the original exemplar by Wagner [54] (figure 6). Unfortunately, it has not been possible to locate the fossil which was probably destroyed during WWII.

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Caturus elongatus has been regarded as a junior synonym of Caturus pachyurus [23,40], Amblysemius pachyurus [23,28], or Amblysemius bellicianus [23,28]. In the absence of a type specimen and considering the deficient original description, neither the potential synonymy nor the validity of the taxon can be confirmed and the species is here regarded as a nomen dubium.

4.9. Caturus maximus Agassiz, 1834 [62]

The original description is not sufficient to distinguish the taxon: ‘Caturus maximus Agass. (Uræus maximus Collect.) Remarquable par le prolongement considérable des rayons extérieurs des deux lobes de la C., qui fait ressembler cette nageoire à celle des Coryphènes. Solenhofen’ [62, p. 13] [Caturus maximus Agass (Uræus maximus Collect.) Remarkable by the considerable extension of the external rays of the two lobes of the caudal fin, which makes this fin resemble that of the Coryphaenes. Solenhofen]. There are two unpublished artworks representing three specimens (LDGSL/614/2/74 and LDGSL/616/2/21/1), which are labelled with this nominal species. The three specimens are from Solnhofen and were part of the collection of Georg Graf von Münster.

The artwork LDGSL/614/2/74 (figure 7a), drawn by G. A. H. Köppel in 1837, includes a partial pectoral girdle and fin (upper drawing), and a partial caudal fin. Specimen CAM SM 11115 (figure 7b) is the counter slab of the fragment of caudal fin in the lower illustration. However, Agassiz [62] describes the two lobes of the caudal fin and, therefore, CAM SM 11115 cannot be identified with the type specimen of C. maximus.

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The illustration LDGSL/616/2/21/1 represents the specimen NHMUK PV P 3583, which is a well preserved postcranium, including the almost complete caudal fin. This specimen fits perfectly the description of Pholidophorus maximus Agassiz, 1844 [63], which is a different taxon. Pholidophorus maximus has been referred to Heterolepidotus by Woodward [40], but direct examination of the specimen confirms that NHMUK PV P 3583 represents a ‘pholidophorid’ and, based on the characteristically finely serrated ganoid scales, the numerous small fringing fulcra and the large distinct dorsal precaudal scute, it can be referred to the Ankylophoridae Gaudant, 1978 [64] (M.E. 2022, personal observation).

Therefore, NHMUK PV P 3583 is undoubtedly the holotype of Pholidophorus maximus Agassiz, 1844 [63], and the holotype of Caturus maximus Agassiz, 1834 [62] is unknown. Although C. maximus has been considered as a junior synonym of C. furcatus [23,28,40], the very incomplete original description does not provide evidence to either confirm or reject this synonymy and the species is regarded as a nomen dubium.

4.10. Caturus microchirus Agassiz, 1834 [62]

The original description is insufficient: ‘Caturus microchirus Agass. (Uræus microchirus Collect.) P. à base large, mais a rayons courts et minces, le premier excepté; rayons branchiostègues antérieurs courts et étroits, insensiblement plus longs et plus larges, au nombre de vingt-quatre à vingt-cinq. Dents de la mâchoire inférieure plus éloignées et plus grandes que celles de la mâchoire supérieure. Solenhofen’ [62, pp. 13–14] [Caturus microchirus Agass. (Uræus microchirus Collect.) Pectoral fins with a broad base, but with short, slender rays, except the first; anterior branchiostegal rays short and narrow, gradually longer and wider, twenty-four to twenty-five in number. Teeth of the lower jaw further apart and larger than those of the upper. Solenhofen]. Specimen CAM SM 11118 is the counterpart of the specimen from the collection of Georg Graf von Münster which is illustrated in LDGSL/614/2/75 (figure 8), watercolour artwork by G. A. H. Köppel in 1837. Since the illustrated specimen is lost, its counterpart CAM SM 11118 is here fixed as the holotype of Caturus microchirus Agassiz, 1834.

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Though Caturus microchirus has been considered as a junior synonym of C. furcatus [23,28,40], the holotype is too incomplete and shows no distinct feature allowing neither to confirm this synonymy nor to validate the nominal species, which must be treated as a nomen dubium.

4.11. Caturus branchiostegus Agassiz, 1834 [62]

The original description is insufficient to distinguish the taxon: ‘Caturus branchiostegus Agass. (Uræus branchiostegus Collect.) Je n'en connais qu'une mâchoire inférieure avec les rayons branchiostègues. Les dents sont rapprochées, la mâchoire courte; les rayons branchiostègues antérieurs plus larges que les suivans. Solenhofen’ [62, p. 14] [Caturus branchiostegus Agass. (Uræus branchiostegus Collect.) I know only one lower jaw with gill rays. The teeth are close together, the jaw short; the anterior branchiostegal rays wider than the posterior ones. Solenhofen]. Attending to the brief original description, the holotype is the specimen illustrated in LDGSL/614/2/75 (figure 8a), watercolour artwork by G. A. H. Köppel in 1837. This very incomplete specimen was part of the collection of Georg Graf von Münster and has not been found.

Specimen NMP Uc275 is illustrated in LDGSL/614/2/66, watercolour sketch by Joseph Rössert between 1833 and 1838 (figure 9). Although similarly incomplete as the holotype, branchiostegal rays are not preserved in this specimen, which despite being well-preserved, is very incomplete, including mainly the two lower jaws, left pterygoids, right quadrate and ventral suborbital, and fragments of the preopercles and left hyomandibula. Since Agassiz [62] (see above) based his new species on a single specimen, NMP Uc275 cannot be considered part of the type series.

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As already indicated by Woodward [40], it is not possible to distinguish this nominal species which represents a nomen dubium.

4.12. Caturus macrodus Agassiz, 1834 [62]

The original description is: ‘Caturus macrodus Agass. (Uræus macrodus Collect.) Espèce encore douteuse, ressemblant beaucoup au Caturus pachyurus, mais dont les mâchoires paraissent plus courtes, les dents plus grandes et très -rapprochées les unes des autres. Eichstædt’ [62, p. 14] [Caturus macrodus Agass. (Uræus macrodus Collect.) A still doubtful species, closely resembling Caturus pachyurus, but whose jaws appear shorter, the teeth larger and very close together. Eichstätt]. Two specimens from Solnhofen in the collection of Georg Graf von Münster were illustrated by G. A. H. Köppel in 1837 (LDGSL/614/2/69 and LDGSL/614/2/70). None of the specimens has been located, and it is nonetheless doubtful if they correspond to the type specimen studied by Agassiz, the provenance of which is indicated Eichstätt.

Caturus macrodus has been regarded as a junior synonym of Caturus furcatus [23,40] or Amblysemius bellicianus [28]. In the absence of a type specimen and considering the deficient original description, the taxon is here regarded as a nomen dubium.

4.13. Caturus latus Münster, 1834 [65]

Holotype SNSB-BSPG AS VIII 263 from Solnhofen (figure 10a). The species name was proposed by Münster, 1834, with a very brief and insufficient description. However, acknowledging the authority of Münster, Agassiz (Agassiz 1839) published an illustration of the holotype, which had been designated by Münster in 1834.

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Caturus latus has been considered as a junior synonym of Caturus furcatus [23,28,40]. However, although the holotype is imperfectly preserved, it is a quite complete fish and our recent revision of this and other referred specimens supports the validity of this species, which is currently under study.

4.14. Caturus angustus Münster, 1839 [67]

Valid as Anaethalion angustus according to Münster [61] with neotype JME-SOS2271 from Eichstätt, Germany, designated by Nybelin [68] as ‘Eichstätt III’ [69].

4.15. Caturus angustissimus Münster, 1839 [67]

Valid as Anaethalion angustissimus according to Münster [61] with neotype NHMUK PV OR 37901 from Solnhofen, Germany, designated by Nybelin [68].

4.16. Caturus ovatus Münster, 1839 [67]

The holotype SNSB-BSPG AS VII 266, from Kelheim (most probably Kapfelberg), Germany, is an incomplete fish preserved in left lateral view, consisting of the almost complete postcranium including all of the fins, except the pectorals. The species is listed as a junior synonym of C. furcatus by Lambers [23,28]. However, the specimen was distinguished as a species of the teleost genus Pholidophorus by Wagner [54], under the name Pholidophorus falcifer.

Although the referral of this species to Pholidophorus should be confirmed with further study, our direct observations on the type specimen confirm that it is a teleost and the name is provisionally referred to as ‘Pholidophorus’ ovatus [67]. In any case, the name Pholidophorus falcifer Wagner, 1863 [54], although it remains available (ICZN Art. 10.6), it is invalid because it is an objective synonym of Caturus ovatus Münster, 1839 [67] (ICZN Art. 23, glossary).

4.17. Caturus granulatus Münster, 1842 [61]

The holotype SNSB-BSPG AS VII 1139, from Kelheim (most probably Kapfelberg), Germany, is a complete fish imperfectly preserved in right lateral view (figure 10b). The original description is very brief: ‘C. granulatus, ein 5 1/2’ langer, vorzüglich gut erhaltener Fisch, mit sehr kleinen granulierten Schuppen, fast wie die Chagrin-Haut eines Hayes; ohne sichtbare Wirbel; der Kopf sehr klein, mit äusserst grossen konischen Zähnen’ [61, p. 44] [C. granulatus, a 5 1/2’ long fish, excellently preserved, with very small granulated scales, almost like the chagrin skin of a shark; without visible vertebrae; the head very small, with extremely large conical teeth].

Woodward [40] was doubtful about the taxonomic validity of Caturus granulatus and Lambers [23,28] differentiated SNSB-BSPG AS VII 1139 from Caturus, and thought it represents the genus Amblysemius regarding the species as a junior synonym of his Amblysemius pachyurus (see above discussion on Amblysemius). Our study of SNSB-BSPG AS VII 1139 supports the validity of Caturus granulatus Münster, 1842 as a distinct species of Amblysemius which is currently under study.

4.18. Caturus obovatus Münster, 1842 [61]

Münster did not figure a type specimen or indicate a collection number, and the brief original description of this nominal taxon is not diagnostic: ‘C. obovatus, ein 3 1/2’ langer, ebenfalls ganz vollständiger Fisch; er hat eine länglich-eiförmige Gestalt, einen grossen Kopf, kleine konische Zähne, feine glatte Schuppen; Wirbel sind in keiner der beiden Hälften sichtbar’ [61, p. 44] [C. obovatus, a fish 3.5 in long, also quite complete; it has an elongated ovoid shape, a large head, small conical teeth, fine smooth scales; vertebrae are not visible in any of the two halves].

Specimen MB.f.12850 (figure 5c) is the only specimen found with the label Caturus obovatus in the old collection of Georg Graf von Münster. Moreover, the fish matches the few features included in the original description of this taxon. In particular, it has exactly the same length (8.5 cm = 3.5 in). Therefore, MB.f.12850 is here designated holotype of Caturus obovatus Münster, 1842 (ICZN Arts. 72.4.1.1 and 74.7).

The species has been considered as a junior synonym of Caturus furcatus [23,28,40], but MB.f.12850 is extremely similar to the holotype of C. macrurus NMP Uc74 (figure 5b), which might represent a distinct taxon. If the validity of this species is confirmed, the name C. macrurus Agassiz, 1833 [41] has priority over C. obovatus Münster, 1842 [61].

4.19. Caturus intermedius Münster, 1842 [61]

No type specimen could be found, and the original description is insufficient to distinguish the taxon: ‘C. intermedius. Auch bei diesem Fisch sind die Wirbel nicht zu erkennen, obgleich, wie bei den vorhergehenden Arten, die Wirbel-Fortsätze u. s. w. sichtbar sind. Ein Theil des Kopfes fehlt; der Körper ist schmal; die glatten Schuppen sind gross u. s. w.’ [61, p. 44] [C. intermedius. In this fish, too, the vertebrae are not visible, although, as in the preceding species, the vertebral processes etc. are visible. A part of the head is missing; the body is narrow; the smooth scales are large, etc.]. Wagner [54] studied the type specimen and referred it to Pholidophorus radians Agassiz, 1834 [62].

Woodward [40] placed Caturus intermedius under synonymy with Pholidophorus macrocephalus and Lambers [23,28] placed it under synonymy with C. furcatus. Neither Münster [61] nor Wagner [54] gives any indication about the type specimen, not even its provenance. In the absence of a type specimen and considering the deficient original description, and the confusing appreciation of this taxon by previous authors, who understood it as either a teleost or a caturid, the taxon is here regarded as a nomen dubium.

4.20. Caturus brevicostatus Münster, 1842 [61]

With only one exception, this nominal species has never been mentioned again after the original description, which is very vague and there is no indication of a type specimen or locality: ‘C. brevicostatus, zeichnet sich durch sehr kurze Flossen und Rippen oder Stachel-Fortsätze aus. Auch an dieser Art fehlen die Wirbel. Sie ist dem Megalurus brevicostatus ähnlich, von welchem sie aber schon durch die gegabelte Schwanz-Flosse hinreichend abweicht’ [61, p. 44] [C. brevicostatus, is characterized by very short fins and ribs or spiny appendages. This species also lacks vertebrae. It is similar to Megalurus brevicostatus, from which it differs sufficiently by the forked tail fin].

Caturus brevicostatus was unknown to Woodward [40, p. 350] and was cautiously listed as a junior synonym of C. furcatus by Lambers [23,28]. Münster [61] gives no indication of the specimen examined and it has not been possible to find any potential holotype. Therefore, the species is regarded as a nomen dubium.

4.21. Caturus angustus Agassiz, 1844 [49]

The name Caturus angustus Agassiz, 1844 is a homonym of Caturus angustus Münster, 1839 [67], but both names are valid because they are currently not cogeneric. The latter taxon is the genotype of Anaethalion White, 1938 [70] (see §4.14).

The original and only known description of C. angustus Agassiz, 1844 is very limited: ‘Espèce très-allongée, remarquable par le développement excessif des fulcres du lobe supérieur de la caudale’ [49, p. 118] [Very elongated species, remarkable for the excessive development of the fulcrum of the upper lobe of the caudal fin]. The fish was later studied by Woodward [71] who provides a complete description of a specimen from the Portlandian, Tithonian, Garsington, Oxford, in the Worcester Museum. Woodward fixed this specimen as the holotype. Although Woodward's description of the specimen is rather detailed, it is not clear if C. angustus Agassiz, 1844 is a species of Caturus and a detailed study of the type specimen is necessary to evaluate the validity of this taxon.

Two unpublished artworks representing the holotype designated by Woodward and its counterpart have been located. The counterpart was illustrated by Joseph Dinkel between 1834 and 1839 (LDGSL/614/2/65). The specimen was part of the collection of William Buckland, but it has not been located in Oxford University Museum of Natural History and the whereabouts of the specimen are unknown (H. Ketchum 2022, personal communication). The watercolour of the holotype (LDGSL/616/2/57/2) was also done by Joseph Dinkel, but later in 1860. However, the artwork is accompanied by a reference to ‘“Recherches sur les Poissons Fossiles” (1833–1843/1844), Vol 2, pt2, [p118]’, indicating that Agassiz studied both part and counterpart of the fish. The whereabouts of the holotype specimen in the Worcester Museum are also unknown.

Caturus angustus Agassiz, 1844 was accepted as valid by Woodward [40], but it is not included in the work of Lambers [23,28]. Pending the localization and study of the type specimen, the taxon is provisionally regarded as a nomen dubium.

4.22. Caturus driani Thiollière, 1851 [47]

The original description is not sufficient to distinguish the species: ‘C'est l'espèce inédite que j'indiquais sous le n. 4 de ma première liste, sans oser en déterminer le genre. A celle époque je n'avais pas encore eu l'occasion de me convaincre de toute l'étendue dans laquelle varient les formes et même la position de la dorsale chez les Caturus. Je ne puis aujourd'hui admettre comme base d'une coupe générique, la circonstance que cette nageoire est placée encore un peu plus en avant des ventrales, qu'elle ne l'est déjà chez le C. velifer; lorsque d'ailleurs aucune autre modification un peu apparente n'existe dans le reste du corps. Ce qui achève de différencier cette espèce de la précédente, c'est que la caudale n'est pas plus grande que chez le C. furcatus; tandis que la dorsale, les ventrales et les pectorales l'étant bien davantage, il n'est pas possible non plus de supposer que ce ne soit là qu'une variété de celle dernière. Ce que je disais des proportions des vertèbres ne doit s'entendre que de leurs apophyses, car, je le répète, pas plus pour celui-ci que pour les autres Caturus trouvés à Cirin, le corps des vertèbres n'existe’ [47, 37–38] [It is the unpublished species which I indicated under n. 4 of my first list, without daring to determine its genus. At that time, I had not yet had the opportunity to convince myself of the full extent to which the forms and even the position of the dorsal fin varies in the Caturus. I cannot now admit as the basis of a generic section the circumstance that this fin is placed even a little further forward of the ventrals than it already is in C. velifer; when, moreover, no other slightly apparent modification exists in the rest of the body. What completes the differentiation of this species from the preceding one, is that the caudal is not larger than in C. furcatus; whereas the dorsal, ventral and pectoral being much larger, it is not possible either to suppose that this is only a variety of the latter. What I said about the proportions of the vertebrae must be understood only in terms of their apophyses, for, I repeat, no more for this one than for the other Caturus found at Cerin, the body of the vertebrae exists]. In this description Thiollière merely describes the morphological differences between his new species and C. velifer, which is not a species of Caturus (see below).

Caturus driani has been considered valid [23,28,40]. However, Thiollière did not designate a holotype or figured a specimen of his C. driani, and it is therefore not possible to be certain about the validity of this nominal taxon which is a nomen dubium. While acknowledging the uncertainty about the validity of Thiollière's nominal species, Saint-Seine [52] proposed to maintain the name of C. driani to designate a species of Cerin, which he distinguished from C. velifer by elasmoid scales in the former species as opposed to the rhomboid scales in the latter. Although Saint-Seine [52] did not fix a type specimen of his C. driani, his description is mainly based on the specimen MHNL20015190, which is indistinguishable from C. furcatus.

4.23. Caturus velifer Thiollière, 1851 [47]

Holotype MHNL20015388 from Cerin, France. The species is valid, but it is not a species of Caturus. It has been excluded from this genus as ‘Pholidophorus’ velifer by Vetter [72, p. 111], and it is currently under study.

4.24. Amblysemius bellicianus Thiollière, 1851 [47]

Holotype MHNL20015164 from Cerin, France (figure 4). Our ongoing research on this taxon based on the type and other referred specimens confirms its validity. Amblysemius bellicianus Thiollière, 1851 is the type species of Amblysemius Agassiz, 1844 (see above).

4.25. Strobilodus giganteus Wagner, 1851 [38]

Valid taxon (see §3.1).

4.26. Caturus ferox Winkler, 1862 [66]

The holotype TM 6901 from Solnhofen, Germany, is an almost complete and well-preserved specimen in left lateral view (figure 10c). The excellent and detailed description by Winkler [66] is literally reproduced and translated in the electronic supplementary material, File.

Caturus ferox has been considered as a junior synonym of Caturus furcatus [23,28,40]. However, our recent revision of the holotype supports the validity of this species, which is currently under study.

4.27. Caturus brevis Winkler, 1862 [66]

Holotype TM 6899 from Solnhofen, Germany [72,73]. Vetter [72] noticed that this specimen is not a Caturus and suggested it could be and exemplar of Pholidophorus micronyx. The specimen TM 6899, with rhomboid ganoid scales, is certainly not a Caturus and needs new study.

4.28. Caturus cyprinoides Wagner, 1863 [54]

The original description is not sufficient to solve the taxonomic status of this nominal species: ‘Nach 3 sehr schönen Doppelplatten aus der Eichstädter Sammlung habe ich diese Art aufgestellt, die nach ihrer Grösse und breiten Leibesform die grösste Aehnlichkeit mit C. latus hat, sich aber sogleich dadurch unterscheidet, dass sie keine ringförmigen Hohlwirbel hat, sondern dass zwischen den kurzen oberen und untern Halbwirbeln ein breiter, glatter, unabgetheilter Zwischenraum liegt, den ehemals die weiche Rückensaite erfüllte. Dazu kommt nun noch, dass die Rückenflosse kürzer und die Schnauze spitziger ist. Das Gebiss ist sehr kräftig. Länge 9″, Rumpfbreite 2″ 71/2″′, Rückenflosse 1″ 2″′ hoch, Schwanzflosse am Aussenrande 2″ 8 bis 11″′. Ein kleineres Exemplar ist nur 7″ lang’ [54, pp. 702–703] [After 3 very beautiful double plates from the Eichstätter collection I have setup this species, which has the greatest resemblance to C. latus according to its size and broad body shape, but immediately differs in that it has no ring-shaped hollow vertebrae, but that between the short upper and lower hemivertebrae is a wide, smooth, unhealed space, which formerly filled the soft dorsal string. In addition, the dorsal fin is shorter and the snout more pointed. The dentition is very strong. Length 9″, trunk width 2″ 71/2″′, dorsal fin 1″ 2″′ high, caudal fin at outer margin 2″ 8 to 11″′. A smaller specimen is only 7″ long].

The species has been placed under synonymy with Caturus furcatus [23,28,40]. The holotype of C. cyprinoides SNSB-BSPG AS V 514 from Eichstätt is a complete specimen rather well preserved in part and counterpart. Our revision of the holotype and comparison with other material indicate it is most probably a junior synonym of C. latus.

4.29. Caturus contractus Wagner, 1863 [54]

Wagner based this species on a single specimen from Solnhofen, Germany, that could not be found in the collections of the BSPG and was probably lost during WWII. Wagner [54] distinguished this species mainly on the body proportions of this specimen compared to three specimens of C. pachyurus and the holotype of C. granulatus. ‘So ähnlich auch diese Art, von der nur ein einziges Exemplar von Solenhofen vorliegt, dem C. pachyurus ist, so unterscheidet sie sich doch von letzterem sehr erheblich durch den gedrängteren und weit robusteren Körperbau, wie diess die vorhin angeführten Maasse ausweisen. Auch ist die hohe Rückenflosse etwas mehr vorgerückt und der Kopf verhältnissmässig grösser und kräftiger. Die Zähne in beiden Kiefern sind zahlreich’ [54, pp. 705–706] [As similar as this species, of which only one specimen from Solenhofen is available, is to C. pachyurus, it differs from the latter very considerably by the more compact and far more robust body shape, as the previously mentioned measurements show. Also, the high dorsal fin is somewhat more advanced and the head is relatively larger and stronger. The teeth in both jaws are numerous]. The few measurements provided by Wagner indicate differences between the compared species. Caturus contractus would have a comparatively deeper body, larger head and more anteriorly placed dorsal fin than C. pachyurus.

The unpublished drawing LDGSL/614/2/77 (figure 11a) intended for Agassiz's ‘Recherches sur les Poissons Fossiles' supports the indication by Woodward [40] that NHMUK PV OR 49127 (figure 11b) is a cast of the type specimen of C. contractus Wagner, 1863. However, the original specimen is lost and NHMUK PV OR 49127 does not show distinct body proportions as proposed by Wagner (1863 #2072). Therefore, C. contractus is here considered a nomen dubium.

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4.30. Caturus gracilis Wagner, 1863 [54]

The name was erected by Wagner for a small fish that he considered a variation of C. macrurus: ‘Wird von Agassiz folgendermassen characterisirt: “kleine Art von ohngefähr 4″ Länge, untersetzt und mit kräftigem Skelete”. Es liegen von dieser Art viele Exemplare von Solenhofen und Eichstädt vor. Was Agassiz vom Skelete angab, bezieht sich nur auf die Knöchernen Fortsätze der Wirbelsäule, nicht aber auf die Wirbel selbst, indem diese gar nicht zur Ausbildung gelangt sind, sondern zwischen ihren Apophysen nur ein breiter, leerer Raum vorhanden ist. Nach ihrer äussern Form ähnelt der C. macrurus zunächst einem kleinen C. cyprinoides; die Rückenlinie ist daher ziemlich stark gewölbt, die Bauchlinie weniger. Der Kopf ist zugespitzt und die Kiefer mit zahlreichen Zähnene besetzt. Die grössten Exemplare haben eine Länge von 4″ 6″′ mit einer Breite von 1″ 3–4″′; die kleinsten sind wenig über 3″ lang und von wechselnder Breite, indem der Rumpf bald robuster, bald schmächtiger ist. Letztere Form habe ich in der Sammlung als C. gracilis bezeichnet; sie bildet jedoch wegen der Uebergänge in die breitere Form nur eine Varietät’ [54, pp. 706–707] [Is characterized by Agassiz as follows: ‘small species of about 4″ length, stocky and with a strong skeleton’. There are many specimens of this species from Solenhofen and Eichstädt. What Agassiz stated of the skeleton refers only to the bony processes of the vertebral column, but not to the vertebrae themselves, in that these have not reached formation at all, but only a broad, empty space is present between their apophyses. According to its external form the C. macrurus resembles at first a small C. cyprinoides; the dorsal line is therefore rather strongly arched, the ventral line less. The head is pointed and the jaws are set with numerous teeth. The largest specimens have a length of 4″ 6″′ with a width of 1″ 3–4″′; the smallest are little over 3″ long and of varying width, in that the trunk is sometimes more robust, sometimes more slender. I have called the latter form C. gracilis in the collection; however, it forms only one variety because of the transitions into the broader form]. However, the name C. gracilis Wagner, 1863 has been considered available and the species is currently under synonymy with Caturus furcatus [23,28,40].

Specimen SNSB-BSPG AS I 1247 from Eichstätt is indicated as the holotype of C. gracilis. The small complete fish is very poorly preserved in left lateral view, and it has not been possible to confirm its potential synonymy with C. furcatus [23,28,40] or the validity as a distinct taxon. The name C. gracilis Wagner, 1863 is a homonym of Caturus gracilis (Agassiz, 1832) [43]. However, since both nominal taxa are considered nomina dubia, it is not possible to establish whether they are cogeneric and therefore it is useless to propose a new name for the junior homonym.

4.31. Caturus fusiformis Wagner, 1863 [54]

Wagner [54] indicated this binomen referring to his previous labelling of two specimens in the collection, but without the intention of naming a new taxon. On the contrary, he undoubtedly referred the two so-labelled specimens to C. elongatus Agassiz, 1834: ‘Noch näher an das Original-Exemplar schliessen sich 2 kleinere von Solenhofen und Eichstädt, die ich in hiesiger Sammlung als C. fusiformis bezeichnete. Bei ihnen verläuft der Rumpf wirklich fast in einer Flucht, indem er von vorn an nach hinten sich ganz allmählig verschmälert; der Kopf ist von gleicher Form wie bei den anderen Exemplaren. Länge 5′, grösste Rumpfbreite 1′ 1″. Man möchte fast eine eigene Art daraus errichten’ [54, p. 704] [Even closer to the original specimen are 2 smaller ones from Solenhofen and Eichstädt, which I labelled in my collection as C. fusiformis. In them the trunk is really almost in alignment, narrowing gradually from the front to the back; the head is of the same shape as in the other specimens. Length 5′, greatest trunk width 1′ 1″. One would almost like to create a separate species thereof].

The name Caturus fusiformis Wagner, 1863 was not proposed as a new name. It must be treated as a name published as synonym, and it is therefore not available (ICZM Arts. 11.5.2 and 11.6).

4.32. Thlattodus suchoides Owen, 1866 [74]

The holotype NHMUK PV OR 41386 is a three dimensionally preserved partial skull from the Kimmeridgian of Norfolk, UK. The general shape of the maxilla and the strong dentition made of large marginal teeth with stout conical caps indicate close resemblance with the specimens of Strobilodus giganteus, supporting Zittel's [75] referral of Owen's species to the latter genus as Strobilodus suchoides.

4.33. Ditaxiodus impar Owen, 1866 [76]

The holotype NHMUK PV OR 46318, from the Kimmeridgian of Oxfordshire, UK, consists of incompletely preserved maxilla and denary bones with teeth. The remains are very similar to the specimens of Thlattodus suchoides and Strobilodus giganteus. Owen distinguished the two species from the Kimmeridge Clay Thlattodus suchoides and Ditaxiodus impar based on the characteristics of their teeth. A thorough analysis of these features is needed to evaluate the validity of these taxa. Pending such a study, the species is here tentatively referred to as Strobilodus impar.

4.34. Caturus segusianus Thiollière, 1873 [53]

The specific name is known from a figure [53, fig. 1, pl. XII], but the species was never described or properly published. Although the name was placed under synonymy with Caturus driaini by Woodward [40] and Saint-Seine [52], C. segusianus is not an available name (ICZN Arts. 11–12).

The specimen figured under the name C. segusianus [53, fig. 1, pl. XII] is MHNL20015190, which has been considered to represent Caturus driani by Gervais (in [53]), or Caturus velifer by Saint-Seine [52]. The recent study of MHNL20015190 confirms that it is a specimen of ‘C.’ velifer, which is not a species of Caturus.

4.35. Caturus cliftoni Woodward, 1895 [40]

Holotype NHMUK PV P 6035 imperfect right maxilla, from the Portlandian (Tithonian), Isle of Portland. The holotype is very fragmentary, but the dentition differs from the teeth of Caturus because they lack the labiolingually compressed and sharply carinate acrodin caps typical of the latter genus. Other specimens referred to this species by Woodward [40] NHMUK PV P 6034 (right dentary), NHMUK PV P 6034a (middle portion of a maxilla) and NHMUK PV OR 42381 (portion of a left maxilla) from the type locality, and NHMUK PV OR 40719 (right maxilla) from the Kimmeridge Clay in Dorsetshire, show similar dentition to the holotype. The characteristics of the teeth suggest that C. cliftoni is a species of Strobilodus and is here tentatively referred to the latter genus. Strobilodus cliftoni n. comb. should be compared in detail not only with Strobilodus giganteus but also with the Kimmeridgean taxa Strobilodus (Thlattodus) suchoides and Strobilodus (Ditaxiodus) impar.

4.36. Caturus deani Gregory, 1923 [77]

Holotype AMNH FF 6371 (7930) from the Upper Jurassic Jagua Formation (Oxfordian) of Cuba (Iturralde-Vinent and Ceballos Izquierdo, 2015). The species is based on an imperfectly preserved skull. Additional, still unstudied specimens are hosted in the collections of the AMNH and MCZ.

4.37. Catutoichthys olsacheri Gouiric-Cavalli, 2016 [78]

Holotype MOZ-Pv 3645 from the Tithonian of Los Catutos, Vaca Muerta Formation, Neuquén, Argentina. The species is based on a rather well-preserved postcranium showing distinct features of the Caturoidea.