Anagaudryceras sanctuarium Raffi and Olivero, 2019

Raffi, María E., Olivero, Eduardo B. & Milanese, Florencia N., 2019, The gaudryceratid ammonoids from the Upper Cretaceous of the James Ross Basin, Antarctica, Acta Palaeontologica Polonica 64 (3), pp. 523-542 : 536-538

Anagaudryceras sanctuarium Raffi and Olivero sp. nov.

Fig. 9G.

ZooBank LSID: urn:lsid:zoobank.org:act:DB4BE481-218C-4CFE-91E6-96514F6338CE

Fig. 9. The gaudryceratid ammonoid Anagaudryceras , from early Cam- → panian− Maastrichtian (Cretaceous), Antarctica, Rabot Formation, Punta Redonda (A, H–J), Snow Hill Island Formation, Sanctuary Cliffs (B–G), and López de Bertodano Formation, Seymour Island (K). A. Anagaudryceras calabozoi Raffi and Olivero sp. nov., CADIC PI 486, neanoconch, the arrow marks the last rib of the neanoconch. B–F. Anagaudryceras subcompressum Raffi and Olivero sp. nov. B. CADIC PI 508, phragmocone and part of the body chamber, in lateral (B 1) and ventral (B 2) views. C. CADIC

PI 506 , holotype, phragmocone and part of the body chamber, in lateral (C 1) and ventral (C 2) views. D . CADIC PI 511 , phragmocone, in lateral (D 1) and ventral (D 2) views. E . CADIC PI 527 , phragmocone and part of the body chamber, in lateral (E 1) and ventral (E 2) views. F . CADIC PI 509 , phragmocone and part of the body chamber, in lateral view. G. Anagaudryceras sanctuarium Raffi and Olivero sp. nov ., CADIC PI 604 , phragmocone and part of the body chamber, in lateral view. H–J. Zelandites pujatoi Raffi and Olivero sp. nov. H . CADIC PI 543 , holotype, phragmocone and part of the body chamber, in lateral view. I . CADIC PI 190 , phragmocone, in lateral view. J . CADIC PI 545 , phragmocone and part of the body chamber, in lateral view. K. Anagaudryceras sp. juvenile 2 , CADIC PI 452 , phragmocone, in lateral (K 1) and ventral (K 2) views. Arrows in B 1, C 1, F, G, H, and I mark the beginning of the body chamber .

Etymology: Derived from the name of the outcrop area Sanctuary Cliffs Nunatak, where the species is well represented.

Holotype: CADIC PI 604 , specimen (D 30 mm) with complete phragmocone and incomplete body chamber (Fig. 9G).

Type locality: Sanctuary Cliffs Nunatak, southern Snow Hill Island, Antarctica.

Type horizon: Campanian/Maastrichtian (Cretaceous), the lower part of the Sanctuary Cliffs Member, Snow Hill Island Formation, Ammonite Assemblage 8.2.

Material. — Three internal molds with phragmocone and part of the body chamber preserved ( CADIC PI 604–606 ). From type locality and horizon .

Diagnosis. —Small Anagaudryceras of round whorl section with contrasting ornamentation during the ontogeny. Inner whorls with fine prorsiradiate lirae; adult body chamber strongly ornamented by dense collars with superimposed lirae.

Description.—Small and evolute shell, with round section, and wide umbilicus ( Table 6) with round umbilical wall and umbilical shoulder. The flanks are subparallel and converge to a gentle ventrolateral shoulder and strongly rounded venter. The phragmocone is ornamented with fine prorsiradiate lirae that arise at the umbilical seam and cross straight on the venter. The body chamber ornament consists of dense lirae and wide and dense band-like collars with superimposed lirae. The neanoconch is smooth.

Remarks.— Anagaudryceras sanctuarium Raffi and Olivero sp. nov. does not resemble any stage of the known species of Anagaudryceras . Anagaudryceras subcompressum Raffi and Olivero sp. nov. is much more compressed (SOM: fig. 7) and with strong constrictions in the first whorls. A. sanctuarium Raffi and Olivero sp. nov. could be confused with some small-sized species of the genus Parajaubertella Matsumoto, 1943 . However, the typically globular round section of this genus does not match the specimens of A. sanctuarium Raffi and Olivero sp. nov. The small size of Anagaudryceras nanum Matsumoto in Matsumoto et al., 1985 from the early Campanian of Japan and Russia, is similar to that of our new species but its body chamber has very low, broad flexed band-like ribs separated by narrow constrictions.

Stratigraphic and geographic range.— Anagaudryceras sanctuarium Raffi and Olivero sp. nov. was recorded in a short stratigraphic interval just above the C32/C31 magnetic chron boundary, which is located approximately at the Campanian/Maastrichtian boundary ( Milanese et al. 2017b). Ammonite Assemblage 8.2 Neograhamites cf. N. kiliani, Snow Hill Island, James Ross Archipelago, Antarctica.