Permonautilidae Barskov & Shilovsky, 2014

Korn, Dieter, 2025, A revised classification of the Carboniferous and Permian Nautilida, European Journal of Taxonomy 1017, pp. 1-85 : 68-69

Family Permonautilidae Barskov & Shilovsky, 2014

Fig. 34

Diagnosis

Family of the superfamily Liroceratoidea with a pachyconic or globular, usually subinvolute to subevolute conch. Whorl profile in the adult stage usually more or less strongly depressed; flanks and venter form a continuous arch in the early forms, the venter can be flattened or concave in advanced forms. Terminal aperture with long lateral shell processes emerging from the umbilical margin. Ornament consisting of fine or coarse growth lines. Septum simple in shape, concavely domed; suture line very simple, almost straight across flanks and venter or with small lobes and saddles.

Included genera

Permonautilus Kruglov, 1933 (Roadian to Wuchiapingian; 10 species).

Alexandronautilus Shimansky, 1962 [synonym of Permonautilus Kruglov, 1933 ].

Remarks

The family Permonautilidae was introduced by Barskov & Shilovsky in Barskov et al. (2014) on the basis of virtually one character to separate it from the Liroceratidae , namely the presence of long lateral shell processes emerging from the umbilical margin. Such a process is apparently absent in the other genera of the superfamily Liroceratoidea . Very similar processes are only known from the family Solenochilidae (suborder Solenochilina ), which is not related to the Permonautilidae . Barskov & Shilovsky in Barskov et al. (2014: 1391) clarified that the Permonautilidae are separated from the Solenochilidae by the position of the siphuncle, which is subcentral or centrodorsal in the Permoceratidae and subventral in the Solenochilidae .

The occurrence of the long shell processes in the Early to Late Carboniferous Solenochilidae and the Middle to Late Permian Permonautilidae is indeed a very interesting phenomenon, as both families belong to two unrelated evolutionary lineages that were probably separated already in the Devonian ( Dzik 1984). Although the distinction between the two families Liroceratidae and Permonautilidae is based on only one character, the separation is still accepted here with reservations.

Figures

Fig. 34. Family Permonautilidae Barskov & Shilovsky, 2014. Permonautilus cornutus (Golovkinsky, 1869), from Barskov et al. (2014). Scale bar units = 5 mm.