Zadelsdorfia zana, Korn & Weyer, 2023

Korn, Dieter & Weyer, Dieter, 2023, The ammonoids from the Gattendorfia Limestone of Oberrödinghausen (Early Carboniferous; Rhenish Mountains, Germany), European Journal of Taxonomy 882, pp. 1-230 : 144-145

Zadelsdorfia zana sp. nov.

urn:lsid:zoobank.org:act:8ABDDAC1-F889-4E3B-8F43-00DCB44E17CA

Tables 81–82

Gattendorfia crassa – Bockwinkel & Ebbighausen 2006: 109, text-figs 26, 27g –j.

Diagnosis

Species of Zadelsdorfia with a thickly discoidal, very evolute conch at 5 mm dm (ww/dm ~0.50; uw/ dm ~0.62); conch at 15 mm dm thinly pachyconic, subevolute (ww/dm ~0.65; uw/dm ~0.35). Whorl profile in the juvenile stage crescent-shaped, at 20 mm dm weakly depressed (ww/wh ~1.45); coiling rate moderately high (WER ~1.85). Venter broadly rounded throughout ontogeny, umbilical margin narrowly rounded in the adult stage. Weak constrictions with concavo-convex course. Suture line with lanceolate, weakly pouched external lobe and lanceolate adventive lobe.

Etymology

Acronym for a Zadelsdorfia species from North Africa.

Material examined

Holotype

MOROCCO • Anti-Atlas, Mfis near Taouz , bed 7; Becker Coll.; illustrated byBockwinkel & Ebbighausen (2006: text-fig. 27g –h); MB.C.3832.2.

Paratypes

MOROCCO • 7 specimens; Anti-Atlas , Mfis near Taouz , bed 7; Bockwinkel & Ebbighausen Coll.; MB.C.3832.1, MB.C.3832.3 –8 .

Description

The species newly described here has been worked on in detail by Bockwinkel & Ebbighausen (2006), so reference can be made here to that description.

Remarks

Zadelsdorfia zana sp. nov. resembles Z. crassa , but the ontogenetic transition from the initial serpenticonic stage to the more involute subadult stage occurs at a smaller diameter of the conch (uw/ dm ~0.25 at 20 mm dm) compared to Z. crassa (uw/dm = 0.35–0.45 at 20 mm dm). In addition, G. zana has constrictions, which are straight on the flank, whereas in Z. crassa they are directed backwards.