Tafadnatoceras elfechtense, Fang & Kröger & Liang & Chen & Song & Jiang & He & Wang & Zeng & Liu & Wei & Wu & Qie, 2025

Fang, Xiang, Kröger, Björn, Liang, Kun, Chen, Qing, Song, Jiaqi, Jiang, Lan, He, Yaoyan, Wang, Chenggang, Zeng, Xiongwei, Liu, Hao, Wei, Kai, Wu, Fafu & Qie, Wenkun, 2025, Late Ordovician cephalopods from Morocco and their implications, Swiss Journal of Palaeontology (37) 144 (1), pp. 1-11 : 5-8

publication ID	https://doi.org/10.1186/s13358-025-00374-5
persistent identifier	https://treatment.plazi.org/id/66120869-FFB7-FFDD-BE47-E7ADFDC0F81E
treatment provided by	Felipe
scientific name	Tafadnatoceras elfechtense
status	sp. nov.

Treatment

Tafadnatoceras elfechtense sp. nov.

Figures 4 View Fig , 5 View Fig , 6 View Fig , 7 View Fig

Etymology: Referring to the type locality, Tanout el Fecht, Morocco.

Holotype: Body chamber with a rather long part of the phragmocone, NIGP207336 View Materials ( Figs. 5C View Fig , 6B, C View Fig , 7 View Fig ).

Paratype: NIGP207334 View Materials ( Figs. 5A View Fig , 6E View Fig ) , NIGP207337 View Materials

( Figs. 5D View Fig , 6A View Fig ), NIGP 207338 ( Figs. 5E View Fig , 6D View Fig ), NIGP 207343

( Figs. 5J View Fig , 6F View Fig ).

Type locality and horizon: Tanout el Fecht, northeastern Anti-Atlas. Upper Tiouririne Formation, Katian Stage, Upper Ordovician Series.

Material: Twelve specimens, NIGP207334 View Materials – NIGP207345 View Materials at Tanout el Fecht, northeastern Anti-Atlas region, Morocco, the Upper Tiouririne Formation, Katian Stage, Upper Ordovician Series .

Diagnosis: Orthoconic phragmocone, with an angle of expansion of ca. 10°; conch cross-section circular; siphuncle central with septal perforation diameter ca. 0.05 of the corresponding conch diameter; siphuncular segments expanded, barrel-shaped; connecting rings adnate to septa, adnation wide; septal necks cyrtochoanitic and brim length equal to adnation length; parietal siphuncular deposits form continuous linings; massive episeptal and hyposeptal deposits.

Description: Te holotype NIGP207336 is a portion of a phragmocone with a length of 47.9 mm and a diameter of 10.9–16.7 mm (angle of expansion ca. 9.6°; Fig. 5C View Fig ). Te conch cross-section is circular. Te cameral height varies between 3.1 and 3.7 mm (0.20–0.34 of the corresponding conch diameter). Te conch surface is nearly smooth, probably due to poor preservation. Te siphuncle is almost central with narrow septal perforation (minimum 0.05 of the corresponding conch diameter). Te septal necks are cyrtochoanitic with a brim ca. 0.22 mm in length and ca. 0.45 mm in width. Te connecting rings are barrel-shaped in the median section ( Fig. 6B, C View Fig , 7 View Fig ). Te expansion of the siphuncular segment at its mid-length has a diameter of 0.18 of the corresponding conch diameter. In this specimen, the connecting ring is adnate to the episeptal surface of the septum for a width of 0.45 mm, equal to the length of corresponding septal necks. Parietal siphuncular deposits form continuous linings. Massive, irregular episeptal and hyposeptal deposits occur.

Other specimens, paratypes NIGP207334 View Materials , NIGP207337 View Materials , NIGP207338 View Materials and NIGP207343 View Materials , reveal siphuncular deposits similar to those of the holotype, containing parietal continuous linings with calcite and argillaceous layers ( Fig. 6A, D–F View Fig ). Te calcite layers become thinner or are absent at the septal foramen. Te septal necks in NIGP207334 View Materials and NIGP207343 View Materials are cyrtochoanitic, with an equal width between brim and area of adnation ( Fig. 6E, F View Fig ). Te connecting rings expand abruptly and bend anteriorly ( Fig. 6E View Fig ).

Remarks: Te ornament of the present material is unknown. Te specimens described above are similar to Tafadnatoceras tiouririnense , in general features such as the angle of conch expansion, the siphuncular shape and position and with respect to the parietal siphuncular deposits with continuous linings. However, the specimens of T. elfechtense sp. nov. possess a wider septal neck brim and connecting ring adnation compared to the type species T. tiouririnense . Moreover, the new species differs in having cameral deposits and anteriorly bent connecting rings.