Antaganides cf. erycinus ( Tagliarini, 1901 ) Branger, 2024

Branger, Patrick, 2024, Antaganides n. gen., a new genus of Middle Jurassic nautiloid, ancestor of Pseudaganides Spath, 1927, with discussion on the phyletic origin of the family Pseudonautilidae, Geodiversitas 46 (14), pp. 471-493 : 474

Antaganides cf. erycinus ( Tagliarini, 1901) , n. comb.

(Figs 3A1-A3; 13A, B)

Nautilus erycinus Tagliarini, 1901 : tav. V, pl. 2-3-4-5.

? Cenoceras sp. 1 aff. bradfordensis – Chirat 1997: pl. 6, fig. 4a, b.

? Cenoceras aff. bradfordensis – Chirat 1997:pl. 14, figs 4-5, pl. 15, fig. 1.

MATERIAL EXAMINED. — France • 2 specimens; Nouvelle-Aquitaine, Parthenay, Sainte-Ouenne, Viaduc de l’Égray ; [46°25’25”N, 0°27’28”W]; Niortense Zone; level 32; Upper Bajocian ; Patrick Branger leg.; MBAN; 2023.PB.N117 (Fig. 3A1-A3), 2023.PB.N130 • 2 specimens; Nouvelle-Aquitaine, Niort; [46°18’25”N, 0°27’42”W]; Niortense Zone; Upper Bajocian ; Patrick Branger leg.; MBAN; 2023. PB.N129 and 2023.PB.N148 ( Fig. 13A, B ).

OCCURRENCE. — Upper Bajocian, Niortense Zone, Polygyralis Subzone.

M EASUREMENTS. — See Table 1.

DESCRIPTION

Small sized nautilus, maximum diameter 55 mm, the diameters of specimens 2023.PB.N117 (Fig. 3A1-A3) and 2023.PB.N130 are 52 and 54 mm respectively. Shell compressed on the last whorl with an oval section except on the body-chamber where the venter flattens. Height rapidly increasing. Juvenile whorls have a subrectangular section with flattened flanks except at the very end of the body-chamber where they are slightly inflated, boarding a closed umbilicus. The aperture is well preserved on 2023. PB.N117 (Fig. 3A1-A3) and is similar to that of Pseudaganides . Suture line ( Fig.4A ) has wide shallow lateral and ventral lobes. The siphuncle is small in diameter, located on the ventral half of the septa, at about one third of the median height of the whorl. On 2023.PB.N129, the two last septa of the phragmocone are approximated, indicating an adult stage. This specimen has also kept the muscle scar on its left side ( Fig. 13A ).

REMARKS

The cited specimens are similar to the examples published under the name Nautilus bradfordensis ( Crick, 1898) by Chirat (1997) from the Garantiana and Parkinsoni Zones that also belong to Upper Bajocian. The type specimen of Antaganides erycinus n. comb. is a little older and occured within the dark grey limestone formation (calcare grigio scuro) near Erice, Western Sicily, whose age is Lower Dogger according to Tagliarini (1901), equating to the Upper Aalenian and Lower Bajocian.

Figures

FIG. 13. — A, Antaganides cf. erycinus (Tagliarini, 1901), n. comb., specimen 2023.PB.N129, with its preserved muscle scar, Niort, Upper Bajocian, Niortense Zone; B, Antaganides cf.erycinus (Tagliarini,1901),n.comb.,specimen 2023.PB.N148, with its siphuncle,viaduc de l’Égray,Upper Bajocian,Niortense Zone;C, Pseudaganides crechensis n. sp.,specimen 2023.PB.N143, newly hatched shell showing its reticulate ornamentation on the phragmocon;D1-D3, Pseudaganides subbiangulatus (d’Orbigny,1850),specimen 2023.PB.N110, full grown shell with itswell preserved aperture,Bougon,Lower Callovian,Gracilis Zone,Patina Subzone,Boginense Horizon; E1-E3, Pseudaganides subbiangulatus, specimen 2023.PB.N112, Niort,Middle Callovian,Anceps Zone,Stuebeli Subzone.*, end of the phragmocone.Scale bars:1 cm.

FIG. 4. — Suture lines of Antaganides n. gen. and Pseudaganides Spath, 1927: A, Antaganides cf. erycinus (Tagliarini,1901), n. comb., 2023.PB.N117; B, Antaganides sauvageti n. gen., n. sp. 2023.PB.N64; C, Antaganides fournieri n. gen., n. sp., 2023.PB.N105; D, Pseudaganides aquitanense n. sp., 2023.PB.N96; E, Pseudaganides buffeventin. sp.,2023.PB.N76; F, Pseudaganides crechensisn. sp., 2023.PB.N107; G, Pseudaganides subbiangulatus (d’Orbigny,1850),2023. PB.N73, Patina Zone; H, Pseudaganides subbiangulatus, 2023.PB.N112, Anceps Zone.