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| Hauffiopteryx typicus (von Huene, 1931)
in Maxwell & Cortés, 2020.
DOI: 10.26879/937
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ABSTRACT
Hauffiopteryx typicus is an Early Jurassic ichthyosaur species from Europe, for which geographically partitioned morphological variation between specimens from England and Germany has been described. We provide a complete anatomical description of the German material to address this taxonomical issue. We also identify and describe a new species of Hauffiopteryx from the southwest German Basin, Hauffiopteryx altera sp. nov., differring from H. typicus in the morphology of the arrangement of cranial elements surrounding the external nares. A phylogenetic analysis recovers the German and English material referred to H. typicus as sister taxa, suggesting that these are indeed conspecific. H. typicus forms a monophyletic group with H. altera and a specimen from the Pliensbachian of Switzerland previously referred to Leptonectes tenuirostris but consistent with H. typicus. We conclude that Hauffiopteryx represents a valid genus, defined by a set of synapomorphies from both the skull and postcranium. Parsimony analysis recovers Hauffiopteryx as sister taxon to Stenopterygius + Ophthalmosauridae.
Keywords: Hauffiopteryx; new species; Posidonienschiefer Formation; Germany; Toarcian; Early Jurassic
SYSTEMATIC PALEONTOLOGY
ICHTHYOPTERYGIA Owen, 1859
ICHTHYOSAURIA Blainville, 1835
PARVIPELVIA Motani, 1999
HAUFFIOPTERYX Maisch, 2008
Type species. Hauffiopteryx typicus (von Huene, 1931)
Revised generic diagnosis. A small- to mid-sized ichthyosaur, 2-3 m in length, with relatively short and slender antorbital rostrum; slight overbite present (unlike Eurhinosaurus, Excalibosaurus in which a substantial overbite is present); prefrontal participating in margin of external naris (unlike Eurhinosaurus, Leptonectes, Stenopterygius); nasals with a greater contribution to the dorsal midline of the rostrum anterior to the external narial opening than the premaxillae (unlike Stenopterygius); prefrontal with larger external exposure on dorsal skull roof than the postfrontal (unlike Stenopterygius); parietal foramen situated anterior to the supratemporal fenestra (situated at the same level as the anterior edge of the supratemporal fenestra in Stenopterygius); supratemporal fenestra small and circular in dorsal view (similar to Eurhinosaurus but unlike Stenopterygius); supratemporal palmate in posterodorsal view (similar to Eurhinosaurus, unlike Stenopterygius); teeth with smooth enamel (unlike Suevoleviathan); gastralia extending posteriorly to the thirty-fifth presacral vertebra (unique feature among Toarcian ichthyosaurs); rib tuberculum and capitulum widely separated in the dorsal region (unlike Temnodontosaurus, Suevoleviathan, Eurhinosaurus); glenoid end of scapula anteriorly expanded (unlike in Temnodontosaurus); coracoid with anterior notch, foramen between humerus, radius, and ulna absent (unlike Suevoleviathan, Temnodontosaurus trigonodon); anterior digit in both fore- and hindfins with notches on the anterior edge (unlike in Suevoleviathan); proximal limb elements angular and forming a tightly articulated mosaic; ischium and pubis thin and styloidal, fused laterally but widely separated medially (autapomorphic); fibula larger than the tibia; hindfin digits converging distally.
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| FIGURE 1. Hauffiopteryx typicus. A, lectotype, GPIT 1491/4; B, SMNS 51552; C, SMNS 80226. Part 1B © SMNS / M. Wahler. |
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| FIGURE 2. Hauffiopteryx typicus, cranial morphology. A–G, overview of cranial morphology. A, lectotype, GPIT 1491/ 4; B, SMNS 51552; C, MHH 9; D, SMNS 80226. E, basioccipital in ventral view (SMNS 80226); F, maxillary and posterior dentary teeth (GPIT 1491/4); G, anterior mandible with displaced teeth (SMNS 80226). Scale bars in cm (parts B, D, E).
Abbreviations: an, angular; bo, basioccipital; de, dentary; hc, hyoid corpus; hy, hyoid element; en, external narial opening; ex, exoccipital; f, frontal; j, jugal; la, lacrimal; lj, lower jaw; mx, maxilla; n, nasal; op, opisthotic; pa, parietal; pal, palatine; pf, prefrontal; pl, palate; pm, premaxilla; po, postorbital; pof, postfrontal; pt, pterygoid; Q, quadrate; qj, quadratojugal; sa, surangular; scr, sclerotic ring; sp, splenial; sq, squamosal; st, supratemporal; s, stapes; utf, supratemporal fenestra.
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| FIGURE 4. Postcranial morphology of Hauffiopteryx typicus. A, anterior neural spines of the lectotype GPIT 1491/4, note the broad axial neural spine of the same height as the neural spine of C3 but twice as wide. B, Fused atlas-axis complex (SMNS 80226); C, gastralia in the mid-dorsal region of SMNS 80226, the arrow indicates the boomerangshaped medial element (see also inset); D, reconstruction of Hauffiopteryx typicus; the shape and position of the dorsal and caudal fins are based on the lectotype. Anterior is to the left in all parts. Scale bars in cm (parts B, C).
Abbreviations: at-ax, atlas-axis complex; ns2, neural spine (axis).
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Hauffiopteryx typicus (von Huene, 1931)
Hauffiopteryx altera sp. nov.
2005 Eurhinosaurus longirostris (Mantell, 1851):
Jäger, p. 29, fig. 23.
Etymology. The specific epithet is derived from
the Latin altera, which means different from/other
and refers to the anatomical divergence from the
type species, H. typicus.
CONCLUSIONS:
We found no evidence that the English and German material referred to the genus Hauffiopteryx represent separate species; however, we do find evidence that two species of Hauffiopteryx were present in the Early Jurassic of the Southwest German Basin: H. typicus and H. altera sp. nov. These two taxa are differentiated primarily based on characters pertaining to the lacrimal, prefrontal, and jugal. In addition, we refer a specimen previously considered to be Leptonectes tenuirostris to Hauffiopteryx typicus, extending the range of the genus into the Pliensbachian. This result is supported by phylogenetic analysis, which recovers Hauffiopteryx as a sister group to Stenopterygius + Ophthalmosauridae. Hauffiopteryx represents a valid genus, defined by a suite of synapomorphies involving both the skull and postcranium. However, the functional and paleoecological significance of these characters differentiating Hauffiopteryx from the superficially similar genus Stenopterygius are unclear.
Erin E. Maxwell and Dirley Cortés. 2020. A Revision of the Early Jurassic Ichthyosaur Hauffiopteryx (Reptilia: Ichthyosauria), and Description of A New Species from southwestern Germany. Palaeontologia Electronica. 23(2); a31. DOI: 10.26879/937
Plain Language Abstract: Hauffiopteryx is a small ichthyosaur, 2–3 meters in length, with small, pointed teeth and large eyes. It is known from the Early Jurassic (~182 million years ago) of southwestern Germany and England, but is most abundant in the Posidonia Shale of southwestern Germany, a world famous Early Jurassic fossil locality. Hauffiopteryx contains only one named species, H. typicus; however, there has been some debate as to whether the German and English finds are actually different species. We examined the anatomy of the German Hauffiopteryx specimens in detail in order to answer this question. This study revealed a second species of Hauffiopteryx from Dotternhausen, Germany, Hauffiopteryx altera sp. nov., differing from H. typicus in skull characteristics. We found no evidence that the English and German specimens referred to Hauffiopteryx typicus represent different species. Additionally, we identified the oldest record of Hauffiopteryx from the Pliensbachian of Switzerland, more than two million years older than the German and English finds. Hauffiopteryx is closely related to Stenopterygius + Ophthalmosauridae, the lineage of ichthyosaurs that includes some of the last representatives of the group.
