identifier	taxonID	type	CVterm	format	language	title	description	additionalInformationURL	UsageTerms	rights	Owner	contributor	creator	bibliographicCitation
C62D808792A553DAAC6C089A822F9793.text	C62D808792A553DAAC6C089A822F9793.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Stenopterygius Jaekel 1904	<div><p>Genus Stenopterygius Jaekel, 1904</p><p>Type species.</p><p>Stenopterygius quadriscissus (Quenstedt, 1856) .</p><p>Other species.</p><p>Stenopterygius triscissus, Stenopterygius longipes (see Remarks), Stenopterygius aaleniensis (Maisch 2008; Maxwell 2012; Maxwell et al. 2012).</p><p>Diagnosis</p><p>(modified from Maxwell (2012)). Upper temporal fenestrae large and wider anteriorly than posteriorly, unlike in Hauffiopteryx and Eurhinosaurus . Mandibular alveolar groove short in adults, not continuing posterior to mid-point of external nares. Suborbital groove on surangular long and deep, similar to Ophthalmosaurus, but unlike Temnodontosaurus and Ichthyosaurus . Angular exposure on posterior lower jaw extensive, but less so than in ophthalmosaurians. Crowns of teeth smooth, lacking macroscopic enamel ornamentation, unlike most ophthalmosaurians and Ichthyosaurus, but similar to Eurhinosaurus and Hauffiopteryx . Scapula with prominent acromial angle; posterior notch of coracoid reduced or absent, as in ophthalmosaurians, but unlike in Ichthyosaurus . Humerus with two distal facets, for articulation with the radius and ulna, shared with all non-ophthalmosaurian ichthyosaurs. Fore-limb with 4 digits, homologous to digits II – V, individual elements tightly packed proximally, notching in leading edge of some elements of the anterior digit shared with many non-ophthalmosaurian ichthyosaurs. Intermedium supporting primarily digit III (i. e. longipinnate, unlike Ichthyosaurus and Ophthalmosaurus). Pelvic girdle bipartite, ischium and pubis fused both medially and laterally to enclose the obturator foramen, shared only with some ophthalmosaurians. Hind-limb with three digits, notching in leading edge of some elements as in many non-ophthalmosaurian ichthyosaurs. Paired limbs disproportionate in length, fore-limb at least twice length of hind-limb, humerus approximately 30 % longer than femur, shared with Ichthyosaurus and Ophthalmosaurus . Presacral vertebrae 44–46; preflexural vertebrae 80 &lt;n &lt;90, similar to Hauffiopteryx (45–46 presacral vertebrae and 81 preflexural vertebrae), but unlike in Eurhinosaurus (preflexural count&gt; 95: McGowan and Motani (2003)) and Ichthyosaurus (preflexural count &lt;80: McGowan and Motani (2003); Massare and Lomax (2018)).</p><p>Remarks to Stenopterygius longipes (Wurstemberger, 1876) .</p><p>The type material of Stenopterygius longipes consists of a large ichthyosaur skeleton, GPIT -PV-30019 (Stöhr and Werneburg (2022): pl. 4 A), mounted on the wall near the ceiling at the GPIT. The specimen shows the classic ‘ head dive’ taphonomic posture, with the anterior rostrum protruding out of the wall in three dimensions, the posterior portion of the skull including the orbits and upper temporal fenestrae compressed and distorted, the anterior vertebral column and rib cage acutely compressed and pushed into the back of the skull and the anterior fore-limbs penetrating into the sediment (Martill 1993; Wahl 2009; Maxwell et al. 2022). Maisch (1998 a) raised questions of specimen authenticity and used these grounds to invalidate S. longipes as a species. In particular, he considered the humeri as having been rotated proximodistally 180 °, in addition to duplication of the right ulna and lack of zeugopodial elements on the left, suggesting the fore-limbs likely do not belong to the same individual as the rest of the skeleton. He concluded that since the fore-limbs likely do not belong with the rest of the skeleton, GPIT -PV-30019 is non-diagnostic and, therefore, declared S. longipes a nomen dubium (Maisch 1998 a).</p><p>Maisch (1998 a) noted that the hind-limbs of GPIT -PV-30019 showed a particular pathological pattern of fusion of proximal elements. However, he failed to note that the fore-limbs, most notably the right fore-limb in which the radius, radiale and intermedium are partially co-ossified, show the same pattern of exostoses and pathological fusion of elements as the hind-limbs (Pardo-Pérez et al. (2019): cited as GPIT no. 83). Re-examination of the skeleton indicates that the humeri are exposed in anterior view, consistent with specimen taphonomy, with the distal end orientated correctly relative to the limb axis. The right humerus is badly fractured and differentially compacted; it is likely that one of the fragments is what Maisch interpreted as a duplicated ulna. In the left limb, the radius is preserved and in articulation with the distal limb elements, although partially overlapped by a fragment of a more posterior element, possibly the ulna. Therefore, it is clear that the fore-limbs and hind-limbs belong to the same individual and there is no reason to assume GPIT -PV-30019 is a composite – with the potential exception of the postflexural tail, a conclusion reached independently by other authors using different lines of evidence (Stöhr and Werneburg 2022).</p><p>GPIT -PV-30019 is a large individual of Stenopterygius . As preserved, the specimen is estimated to be at least 3.4 m in length (although the post-flexural tail may not belong to the same specimen: Stöhr and Werneburg (2022)), with a skull length of at least 550 mm (given the compaction of the orbital and cheek region, this is an underestimate); humeri approximately 123 mm in length and femora 96 mm in length. Although total and skull length cannot be accurately measured, the limb bones are far longer than those of the largest documented individual referable to S. quadriscissus; the femur, ischiopubis and hind-limb are too large and robust to be consistent with S. triscissus . The pectoral limbs are long and wing-like. For these reasons, we conclude that Stenopterygius longipes (Wurstemberger, 1876) is consistent with the current taxonomic concept of Stenopterygius uniter von Huene, 1931 sensu Maisch (2008) and, therefore, is the senior synonym.</p><p>Remarks to Magnipterygius huenei Maisch &amp; Matzke, 2022 .</p><p>Magnipterygius huenei, from the Posidonienschiefer Formation of Germany and represented only by its holotype SMNS 96922 (Fig. 5 A), was described as a small stenopterygiid. It was diagnosed to the exclusion of other Toarcian Stenopterygius species by its small size, low number of presacral and preflexural vertebrae (36 presacral and 70 preflexural, according to Maisch and Matzke (2022)), a parietal foramen enclosed by frontals and pre- and postflexural caudal regions almost equal in length. Numerous comparisons of this specimen with S. triscissus were undertaken during the initial description (Maisch and Matzke 2022), but none with S. quadriscissus .</p><p>Maisch and Matzke (2022) considered SMNS 96922 to be at least subadult (= postnatal 2, osteologically immature adult: Miedema and Maxwell (2022)). However, the proximal articular surface of the humerus is flat, the humeral shaft has a roughened texture, the sutures between proximal forelimb elements remain open, the radius is unnotched and the notches on the proximal and distal carpals of digit II are weakly developed, all of which are consistent with postnatal stage 1 of Stenopterygius (Johnson 1977; Maxwell et al. 2014). In the skull, the parietal bears a dorsal triangular platform (Fig. 5 C), present in postnatal stage 1 of Stenopterygius, but absent in later stages. The ossification centre of the parietal also remains visible, indicated by radiating bone fibres, and a weakly developed parietal shelf is present, both characters of which are consistent with postnatal stage 1, but not with more osteologically mature individuals. The jugal is semi-lunate to semi-angular, whereas it is very angular from postnatal stage 2 onwards. Some ontogenetic characters, diagnostic of postnatal stage 1, are also visible on the frontal, such as its more quadrangular outline, the interfrontal suture being less ossified and the absence of medial process anterior to the anterior border of the parietal foramen (Miedema and Maxwell 2022). In addition to these qualitative characters, skull length is estimated at 270 mm (Maisch and Matzke 2022), which is consistent with postnatal stage 1 of Stenopterygius (Miedema and Maxwell 2022) . Therefore, the small body size in SMNS 96922 can be attributed to an earlier ontogenetic stage than previously inferred, rather than a species-level characteristic.</p><p>Magnipterygius huenei was diagnosed by a low vertebral count (36 presacral and 34 tailstock vertebrae according to Maisch and Matzke (2022)) relative to S. triscissus . The low presacral count can be attributed to taphonomic factors: headfirst seafloor arrival in ichthyosaurs can displace the cervical centra inside the skull such that they are not externally visible (Maxwell et al. 2022; Johnson et al. 2025) and embedding depth of the anterior rostrum in SMNS 96922 clearly supports such a taphonomic interpretation (Fig. 5 D). By counting the number of presacral ribs instead of centra, a count of 45 presacral vertebrae is obtained. Thirty-four tailstock vertebrae are present, which is not typically consistent with S. triscissus (Maisch and Matzke 2022), but well within the range of S. quadriscissus (Fig. 3 D). The equal length of the postflexural region and tailstock was also cited as diagnostic for Magnipterygius to the exclusion of S. triscissus; a tailstock almost equal in length to the postflexural vertebral column is also characteristic of S. quadriscissus, which shows a longer postflexural region than S. triscissus (Fig. 3 C). A more in-depth comparison with perinatal S. quadriscissus specimens gives similar results (postflexural length / total caudal length = 0.46 for SMNS 96922; vs. 0.47 for perinatal soft-tissue specimen of S. quadriscissus SMNS 12821).</p><p>Closer examination of the parietal foramen of SMNS 96922 (Fig. 5 B) revealed that it is not totally enclosed by the frontals, with the parietals participating posteriorly (contra Maisch and Matzke (2022)), as in all Stenopterygius species (Lomax et al. 2020). A jugal – premaxillary contact, with the ventral border of the external nares only composed by the extensive subnarial process of the premaxilla was also cited as differentiating Stenopterygius and Magnipterygius (Maisch and Matzke 2022) . However, as the lacrimal has clearly been anteriorly displaced from its articulation with the prefrontal (similar to SMNS 55110; see below); this anterior displacement has also affected the jugal, forcing it into contact with the subnarial process of the premaxilla and leading to the external nares being foreshortened. This type of displacement is typical of head-first arrival specimens (Wahl 2009; reviewed by Johnson et al. (2025)). The absence of a sagittal crest and the flat appearance of the parietal are due to ontogeny (see above). Finally, the scapula to does not appear any more slender than in other scapulae of juvenile Stenopterygius (pers. observ. FM).</p><p>Lastly, Maisch and Matzke (2022) cited the posterior insertion of the soft tissue dorsal fin, beginning at the 39 th presacral centrum (= 30 th of Maisch and Matzke (2022)), with the apex situated opposite or posterior to the presacral-caudal transition. In comparison, in other Stenopterygius specimens, the dorsal fin inserts more anteriorly and the apex is well anterior to the presacral-caudal transition. While the position of the apex appears to be somewhat ontogenetically dependent (e. g. the apex is opposite or near-opposite the presacral-caudal transition in perinatal specimens, for example, SMNS 12821), the anterior insertion is around centrum ~ 32; i. e. still well anterior to that of Magnipterygius . In the absence of osteological differences, soft-tissue slippage during decay appears to be the most plausible explanation.</p><p>In addition to the similarities with Stenopterygius quadriscissus in caudal proportions, the length of the ulnar facet is inferior to the length of the radial facet of the intermedium in SMNS 96922 (Uf / Rf = 0.79); this value is only consistent with S. quadriscissus amongst Toarcian species of Stenopterygius .</p><p>Therefore, based on both ontogenetic and qualitative criteria, Magnipterygius huenei cannot be differentiated from Stenopterygius quadriscissus and we consider M. huenei to be a subjective junior synonym of the latter taxon.</p></div>	https://treatment.plazi.org/id/C62D808792A553DAAC6C089A822F9793	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Biot, Timothée;Lomax, Dean R.;Miedema, Feiko;Maxwell, Erin E.	Biot, Timothée, Lomax, Dean R., Miedema, Feiko, Maxwell, Erin E. (2026): A well-preserved specimen of Stenopterygius quadriscissus (Reptilia, Ichthyosauria) from the Early Jurassic (Toarcian) of Yorkshire, UK and new insights into species delineation in the genus. Fossil Record 29 (1): 185-210, DOI: 10.3897/fr.29.185733
9BE7B818F0FB5BCB872D51BE41C0E6C3.text	9BE7B818F0FB5BCB872D51BE41C0E6C3.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Stenopterygius quadriscissus (Quenstedt 1856)	<div><p>Stenopterygius quadriscissus (Quenstedt, 1856)</p><p>Partial synonymy.</p><p>Stenopterygius eos von Huene, 1931: Fraas 1891 pl. 4, fig. 1 (lectotype sensu Maisch (2008)).</p><p>Stenopterygius incessus von Huene, 1931: pl. 1, fig. 1.</p><p>Stenopterygius promegacephalus von Huene, 1949: Maisch (2008) pl. 8, fig. 1.</p><p>Stenopterygius macrophasma McGowan, 1979: pl. 3, fig. 2.</p><p>Magnipterygius huenei Maisch &amp; Matzke, 2022: p. 170, figs 2–12.</p><p>Lectotype.</p><p>GPIT -PV-30028; for a list of paralectotypes, see Hungerbühler (1994).</p><p>Diagnosis.</p><p>Modified from Maxwell (2012); characters indicated by an asterisk are new. Moderately large form, maximum length approximately 3.5 m, antorbital segment moderately long, approximately two-thirds the length of the lower jaw; tooth reduction in individuals greater than 2 m total length; forelimb shorter than in Stenopterygius longipes, longer than in S. triscissus; ulnar facet of intermedium usually shorter than radial facet * (ratio usually &lt;1 and never&gt; 1.07; radial facet longer in S. triscissus (1.20–1.75) and S. longipes (1.03–1.18)); premaxilla and lower jaw shorter relative to length of humerus, femur, scapula and ischiopubis than in S. longipes or S. triscissus . In osteologically mature individuals, distal tarsal II strongly notched with smaller surface area than the astragalus or calcaneum, unlike in S. longipes; body deeper than S. longipes and S. triscissus; tailstock vertebral count 34–40 in adults and large juveniles * (mean = 35.6; higher in S. triscissus: 34–44, mean = 39.8); postflexural length 0.35–0.44 total caudal length in adults * (reduced in S. triscissus: 0.31–0.36).</p><p>Remarks.</p><p>Juvenile S. quadriscissus (specimens with lower jaw lengths between 200 and 400 mm) can have a relative postflexural length either longer or shorter than adult individuals (ratio to total caudal length = 0.34–0.47). If the length of the ulnar facet of the intermedium is longer than the radial facet (Uf / Rf = 1.0–1.07), comparisons with S. longipes are necessary to correctly refer a specimen to species.</p><p>Description of SMNS 55110, the Ravenscar Stenopterygius .</p><p>SMNS 55110 is a nearly complete articulated skeleton exposed on its right lateral side for most of the body length (Fig. 6 A). The skull is exposed ventro-laterally, revealing the mandible, but not the majority of skull roof. The fore-limbs and the pectoral girdle have become detached from the axial skeleton, as have the majority of the ribs. Nevertheless, the fore-limbs and the pectoral girdle remain completely articulated as an anatomical unit. The hind-limbs and the pelvic girdle are missing. Some parts of the posterodorsal skull are also disarticulated, including both scleral rings, supratemporals and postorbitals and the left postfrontal, quadrate and squamosal. The total length of the specimen is 145.8 cm (Table 1). It is worth noting that the excellent preservation of the specimen is only highlighted due to the excellent preparation of the skeleton, something that most historical specimens lack. More recently collected material from the Whitby area residing in private collections is similarly well-prepared and displays similar levels of preservation (DRL pers. obs.).</p></div>	https://treatment.plazi.org/id/9BE7B818F0FB5BCB872D51BE41C0E6C3	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Biot, Timothée;Lomax, Dean R.;Miedema, Feiko;Maxwell, Erin E.	Biot, Timothée, Lomax, Dean R., Miedema, Feiko, Maxwell, Erin E. (2026): A well-preserved specimen of Stenopterygius quadriscissus (Reptilia, Ichthyosauria) from the Early Jurassic (Toarcian) of Yorkshire, UK and new insights into species delineation in the genus. Fossil Record 29 (1): 185-210, DOI: 10.3897/fr.29.185733
