Vestinautilus papilio, Korn & Bockwinkel, 2022

Korn, Dieter & Bockwinkel, Jürgen, 2022, Early Carboniferous nautiloids from the Central Sahara, southern Algeria, European Journal of Taxonomy 831, pp. 67-108 : 88-89

Vestinautilus papilio sp. nov.

urn:lsid:zoobank.org:act:F7146ECD-A229-4889-863C-4160E41BF1C4

Figs 16–17 , Table 9

Diagnosis

Species of Vestinautilus with moderately depressed, rounded-trapezoidal whorl profile (ww/wh ~1.60– 1.80), venter weakly flattened, with three longitudinal grooves on each side, ventrolateral shoulder subangular. Whorls weakly embracing. Ornament with two or three weak but sharp ridges on the flank.

Etymology

From the Latin ‘ papilio ’, meaning ‘butterfly’ and referring to the shape of the whorl profile.

Type material

Holotype ALGERIA • Mouydir , south of Oued Temertasset (locality MOU-D1); Argiles de Teguentour (Upper Pericyclus-Progoniatites Assemblage; early late Tournaisian); Korn et al. 2002 Coll.; illustrated in Fig. 16A ; MB.C.30470.1 .

Paratypes ALGERIA • 1 specimen; Mouydir , south of Oued Temertasset (locality MOU-D1); Argiles de Teguentour (Upper Pericyclus-Progoniatites Assemblage; early late Tournaisian); Korn et al. 2002 Coll.; illustrated in Fig. 16B ; MB.C.30470.2 • 10 specimens; Mouydir , south of Oued Temertasset (localities MOU-D1, MOU-Z); Argiles de Teguentour (Upper Pericyclus-Progoniatites Assemblage; early late Tournaisian); Korn et al. 2002 Coll.; MB.C.30470.3 – MB.C.30470.6 , MB.C.30471.1 – MB.C.30470.6 .

Description

Holotype MB.C.30470.1 is a phragocone segment of about a quarter whorl with almost 10 mm whorl height; it consists of four chambers ( Fig. 16A ). The whorl profile is depressed (ww/wh =1.62) and kidney-shaped with a rounded venter, subangular ventrolateral shoulder and a convex curved area encompassing the flanks and umbilical wall ( Fig. 17A ). The whorl weakly encloses the preceding whorl. On the venter there are three longitudinal marginal grooves on each side; the ventrolateral shoulder is defined by two slightly raised edges. The flanks bear two coarse spiral lines near the ventrolateral shoulder. The suture line has a low amplitude course; it shows a very low external saddle and very shallow lateral lobe. Only the internal lobe is deeper and has a blunt V-shaped form ( Fig. 17B ).

Paratype MB.C.30470.2 shows, at a whorl height of 6 mm ( Fig. 16B ), a largely similar morphology to the holotype. However, there is the big difference that it does not have a concave whorl zone ( Fig. 17C ),

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probably due to its small size. Furthermore, the whorl profile is broader (ww/wh = 1.82). The suture line is almost straight; there is no internal lobe ( Fig. 17D ).

Remarks

Vestinautilus papilio sp. nov. belongs to the species of the genus with a moderately depressed whorl profile (ww/wh ~ 1.70), a character that distinguishes the new species from most of the other species of the genus with weakly embracing whorls. Another criterion that distinguishes the new species is the rather weak longitudinal sculpture.

Figures

Fig. 16. Vestinautilus papilio sp. nov. from Oued Temertasset (both Korn et al. 2002 Coll.). A. Holotype MB.C.30470.1. B. Paratype MB.C.30470.2. Scale bar units =1 mm

Fig. 17. Vestinautilus papilio sp. nov. from Oued Temertasset (both Korn et al. 2002 Coll.). A. Whorl profile of holotype MB.C.30470.1. B. Suture line of holotype MB.C.30470.1, at ww =15.5 mm, wh=9.5 mm.C. Whorl profile of paratype MB.C.30470.2. D. Suture line of paratype MB.C.30470.2, at ww =10.3 mm, wh= 5.6 mm. Scale bar units= 1 mm.

Tables

Table 9. Conch dimensions (in mm) and ratios of Vestinautilus papilio sp. nov.

Specimen	dm	ww	wh	uw	ah	ww/dm	ww/wh	uw/dm	WER	IZW
MB.C.30470.1	–	15.9	9.8	–	–	–	1.62	–	–	–
MB.C.30470.2	–	10.4	5.7	–	–	–	1.82	–	–	–