Hauffiopteryx typicus (von Huene, 1931)

Maxwell, Erin E. & Cortés, Dirley, 2020, A revision of the Early Jurassic ichthyosaur Hauffiopteryx (Reptilia: Ichthyosauria), and description of a new species from southwestern Germany, Palaeontologia Electronica (a 31) 23 (2), pp. 1-43 : 3-4

Hauffiopteryx typicus (von Huene, 1931)

Figures 1-5

Lectotype. GPIT 1491 /4; a complete skeleton with partial preserved soft-tissue outline in left lateral view. GPIT 1491 /4; a complete skeleton with partial preserved soft-tissue outline in left lateral view ( Figure 1A ).

Geographical distribution. Baden-Württemberg, Germany; Ilminster ( UK) (Maisch, 2008); Solothurn, Switzerland (see discussion for details).

Stratigraphic distribution. Late Pliensbachian, margaritatus Zone; lower Toarcian, tenuicostatum Zone, semicelatum Subzone– serpentinum Zone, exaratum Subzone (SWGB: beds εII 3- εII 4/5). Note that according to the specimen label, SMNS 51552 originates from bed εII 3, rather than εII 2 as stated elsewhere (Maisch, 2008). Peak abundance occurs in εII 4, where material referred to Hauffiopteryx represents a substantial percentage of all small ichthyosaurs recovered (Maxwell and Vincent, 2016).

MAXWELL & CORTÉS: REVISION OF HAUFFIOPTERYX

Emended diagnosis. Hauffiopteryx typicus can be distinguished from other species of Hauffiopteryx by a triradiate lacrimal forming the posterior border of the external narial opening, deepest lateral exposure of the maxilla located ventral to the posterior half of the external narial opening, a large, rounded orbit, and nasals with pronounced dorsal inflection at the anterior orbital margin.

Referred specimens. Of the material examined, GPIT 1491/4, GPIT /RE/12905, MHH 9, SMNS 51552, and SMNS 80226 can be confidently referred to H. typicus ( Figures 1-3 ). The English material referred to Hauffiopteryx is also consistent with H. typicus , as is NMO 26575 from the Pliensbachian of Switzerland (see discussion for details).

Figures

FIGURE 1. Hauffiopteryx typicus. A, lectotype, GPIT 1491/4; B, SMNS 51552; C, SMNS 80226. Part 1B © SMNS / M. Wahler.

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.

FIGURE 3. Hauffiopteryx typicus, cranial morphology of GPIT/RE/12905. A, lateral view; B; dorsal view of posterior skull roof. Abbreviations: an, angular; bo, basioccipital; de, dentary; en, external narial opening; ex, exoccipital; f, frontal; j, jugal; la, lacrimal; mx, maxilla; n, nasal; pa, parietal; pf, prefrontal; pm, premaxilla; po, postorbital; pof, postfrontal; sa, surangular; scr, sclerotic ring; sq, squamosal; st, supratemporal; utf, supratemporal fenestra.

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).

FIGURE 5. Hauffiopteryx typicus, pectoral girdle, and forelimb. A, pectoral girdle and humerus in ventral view (SMNS 80226); B, left forelimb in dorsal view (lectotype GPIT 1491/4); C, coracoids and left forelimb in ventral view (SMNS 51552). Scale bars in cm (parts A, C). Abbreviations: 2–4, distal carpals; cl, clavicle; co (r/l), right and left coracoids; H, humerus; i, intermedium; ic, interclavicle; pi, pisiform; R, radius; re, radiale; sc, scapula; U, ulna; ue, ulnare; v, metacarpal V.