Fig. 1

Holotype of Antarctichthys longipectoralis from the Snow Hill Island Formation, Upper Cretaceous of Antarctica. Photograph of the external surface of the specimen (A.a) and rendering of the bones inside the bone matrix in dorsal (A.b) and ventral views (A.c). The articulated parasphenoid and basioccipital in ventral view (B). The supraethmoid in dorsal (C.a) and ventral views (C.b). The articulation between the exoccipitals and basioccipital in posterior view (D). The articulation between the exoccipital, basioccipital and the first vertebra in left lateral view (E). The articulation between the prootics, exoccipitals and basioccipital in dorsal view (F). Right ceratobranchial in anterior (G.a), posterior (G.b), medial (G.c), and lateral (G.d). Right third ceratobranchial in anterior (H.a), posterior (H.b), medial (H.c), and lateral (H.d). Right indeterminate epibranchial in anterior (I.a), posterior (I.b), medial (I.c), lateral (I.d), and articular (I.e). Right fourth ceratobranchial in anterior (J.a), posterior (J.b), medial (J.c), and lateral (J.d). Right second epibranchial in (K.a), posterior (K.b), medial (K.c), lateral (K.d), and articular (K.e). Right indeterminate epibranchial in anterior (L.a), posterior (L.b), medial (L.c), and lateral (L.d). Left indeterminate pharingobranchial in anterior (M.a), posterior (M.b), medial (M.c), and lateral (M.d). The right pectoral girdle and fins, with the semi-articulation between coracoid, scapula and pectoral fins in medial (N.a) and lateral views (N.b). Vertebral series in articulation from first to 17th vertebra in ventral (O.a) and dorsal views (O.b). The 17th vertebra in anterior (P.a), posterior (P.b), left lateral (P.c), right lateral (P.d), dorsal (P.e), and ventral (P.f). Abbreviations: ANG, anguloarticular; ASPH, autosphenotic; CBR, ceratobranchial; CL, cleithrum; COR, coracoid; EBR, epibranchial; EPO, epioccipital; EXO, exoccipital; f.jug, jugular foramen; FR, frontal; HM, hyomandibula; IO, infraorbital; LET, lateral ethmoid; MPT, metapterygoid; na, neural arch; noc, notochordal canal; ns, neural spine; ot, otolith; PA, parietal; PAS, parasphenoid; PBR, pharingobranchial; pect.f, pectoral fins; PELV, pelvic bones; pl.r, pleural rib; poz, postzygapophysis; PRO, prootic; prz, prezygapophysis; PTO, pterotic; Q, quadrate; SC, scapula; SET, supraethmoid; SOC, supraoccipital; so.s.c, supraorbital sensory canal; SY, symplectic; tps, transverse process; V, vertebra; vc, vertebral centrum; VO, vomer. Scale bars equal to 10 mm in A, 1 mm in B-N and P, and 5 mm in O.