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 Author Branger, Patrick 4 rue Franche F- 79410 Cherveux (France) patrick.branger@wanadoo.fr text Geodiversitas 2024 2024-10-03 46 14 471 493 https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/g2024v46a14.pdf journal article 304151 10.5252/geodiversitas2024v46a14 a6dcf4e3-2ba8-4c57-a797-1e57727505c5 1638-9395 13884433 urn:lsid:zoobank.org:pub:2C97C1BD-2DAA-485A-8AE0-2E3DD501D5F2 Genus Pseudaganides Spath, 1927 Pseudaganides Spath, 1927: 22-25 . TYPE SPECIES . — Nautilus kutchensis Waagen, 1873 , by original designation, from the Callovian of Kutch, India . COMPOSITION OF THE GENUS . — Six nominal species are assigned to this new genus within Bathonian and Callovian, Pseudaganides aquitanense n. sp. from Upper Bathonian, Retrocostatum Zone, Pseudaganides buffeventi n. sp. , Lower Callovian, Bullatus Zone, Pseudaganides crechensis n. sp. , Lower Callovian, Gracilis Zone, Prahecquense Subzone , Pseudaganides subbiangulatus and Pseudaganides dimidiatus Marchand & Tintant, 1971 , from the Lower to Middle Callovian, Patina Subzone, Boginense Horizon to the Anceps Zone, Bannense Subzone and Pseudaganides aganiticus (Schlotheim, 1820) , Upper Callovian to Lower Oxfordian. Many other Pseudaganides from the Upper Jurassic (von Loesch 1914 ) have also to be included within the genus, a revision of this material would be necessary. Based on the angular shape of the ventral lobe, Shimansky & Erlanger (1955) distinguished the genus Xenocheilus Shimansky, 1957 that extends from Upper Oxfordian to Lower Cretaceous beds. FIG . 11. — A1-A3 , Antaganides grulkei n. gen., n. sp. , holotype ( 2023.PB.N97 ), adult shell, les Hauts-de-Rochefort quarry, Middle Bathonian, Progracilis Zone; B1-B3 , Antaganides grulkei n. gen., n. sp. , specimen 2023.PB.N134 , Champs-Albert near la Crèche, Upper Bathonian, base of the Retrocostatum Zone; C1-C3 , Pseudaganides aquitanense n. sp. , holotype ( 2023.PB.N96 ), adult shell, Aiffres, Upper Bathonian, Retrocostatum Zone; D1 , D2 , Pseudaganides aquitanense n. sp. ,specimen 2023.PB.N106 , Champs-Albert near la Crèche,Upper Bathonian, Retrocostatum Zone; E1 , E2 , Pseudaganides aquitanense n. sp. , paratype ( 2023.PB.N124 ), bed 8b, Buffevent quarry near Niort, Upper Bathonian, Retrocostatum Zone. * , end of the phragmocone. Scale bars: 1 cm. TABLE 5. — Measurements (D, H, W, U, P, L, in mm) for Pseudaganides aquitanense n. sp.

n°	D	H	h	W	w	U	u	W/H	P	L	%
2023.PB.N96	61 43	36 27	0.59 0.62	32 19	0.52 0.44	0 0	0 0	0.88 0.7	6 –	19 –	31 –
2023.PB.N106	58	32	0.55	29	0.5	3	0.05	0.9	7	19	36
2023.PB.N124	52 48	29 21	0.55 0.43	23 16	0.44 0.33	2 0	0.04 –	0.79 0.76	5.5 –	16 –	34 –
2023.PB.N125	44	26	0.59	20	0.45	4	0.09	0.76	5	17	29

CHARACTERIZATION AND REMARKS Genus Pseudaganides is a group including small to Middle sized nautiloids, less than 15 centimeters in diameter, mostly around 10 centimeters or less. Shells are compressed, bearing goniatitic suture lines at all growth stages. These suture lines are characterized by a deep lateral lobe, a dorsal saddle on the entire phragmocone and a ventro-lateral saddle. The ventral lobe is sometimes missing. In most stages of coiling the umbilicus is closed. On the inner whorls, the venter is rounded and flattens, sometimes slightly concave, on the body-chamber. As pointed out by Jeannet (1948 : fig. 4) for P. frickensis , the opening of the shell is rather particular, lateral borders are quite straight, starting from the umbilicus with a spiny shaped beginning ( Figs 13D 1 ; 15C). A deep ventral sinus is always present. The siphuncle is typically close to the venter part of the shell. Pseudaganides is known from the top of the Bathonian to the end of the Jurassic from which many new species were described (von Loesch 1914 ). P. portlandicus ( Foord & Crick 1890 ) is atypical, showing an oval and larger shell. It could belong to another genus. All the specimens from the Lower Jurassic to Lower Middle Jurassic with folded suture lines are now gathered within the genus Belmonticeras Rulleau, 2008 . From a palaeogeographical point of view, Pseudaganides seems to be a typical faunal element from the Tethyan realm sensu Westerman (2000) and has not yet been reported from the Arabian realm ( Tintant 1987 ). Due to the ventral position of the siphuncle and the strong folding of the septum sutures, it is generally accepted that species of the genus Pseudaganides were cephalopods adapted to moderately deepwater environments ( Tintant 1987 ).