Gattendorfiinae Bartzsch & Weyer, 1987

Korn, Dieter & Weyer, Dieter, 2023, The ammonoids from the Gattendorfia Limestone of Gattendorf (Devonian-Carboniferous boundary; Upper Franconia, Germany), European Journal of Taxonomy 883, pp. 1-61 : 45-47

Subfamily Gattendorfiinae Bartzsch & Weyer, 1987

Diagnosis

Subfamily of the family Gattendorfiidae with subevolute to evolute inner whorls, adult stage subinvolute to evolute. Ornament usually with coarse rursiradiate growth lines; in some species with radial folds but usually without sharp ribs.

Subfamily composition

In total, about 75 species of the Gattendorfiinae have been described so far. They belong to the genera: Gattendorfia Schindewolf, 1920 (10 species); Kazakhstania Librovitch, 1940 (9 species); Zadelsdorfia Weyer, 1972 (32 species); Gattenpleura Weyer, 1976 (3 species); Hasselbachia Korn & Weyer, 2003 (4 species) and Weyerella Bockwinkel & Ebbighausen, 2006 (17 species).

Remarks

Morphology The morphology within the subfamily Gattendorfiinae is very diverse and it is hardly possible to find a common character for all species. Such a character could possibly be the rursiradiate course of the growth lines.

All species of the subfamily share the character of widely umbilicate juvenile whorls; however, the umbilicus is almost never completely closed during ontogeny. Therefore, the morphology of the adult stage is highly variable and can range from serpenticonic ( Kazakhstania and some species of Gattendorfia ) to moderately umbilicate and molariform ( Weyerella ) to goniatitoid with a narrow umbilicus ( Zadelsdorfia ). Almost all species of the Gattendorfiinae have a low coiling rate (WER usually between 1.50 and 1.75 and only rarely higher).

The ornament often consists of rather coarse, mostly rursiradiate growth lines on the flank, which form a wide ventral sinus of varying depth. Spiral lines are rare ( Weyerella reticulum ) and ribs appear in Gattenpleura and some species of Gattendorfia . Species of the genera Gattendorfia and Kazakhstania often have shell constrictions; in Hasselbachia they are limited to the flanks as short notches.

Ontogeny

In the subfamily Gattendorfiinae , the complexity of ontogeny depends on the adult conch shape. While species with an almost serpenticonic adult stage show very simple ontogenetic trajectories, species with a goniatitoid adult stage ( Gattendorfia , Zadelsdorfia , Gattenpleura , Hasselbachia ) usually have very complex ontogenetic trajectories. This was demonstrated using the example of Zadelsdorfia crassa by Korn & Vöhringer (2004); in this species the trajectory of the ww/dm ratio is conspicuously triphasic. There is also a very marked change in whorl profiles during ontogeny; in Z. crassa , kidney-shaped, trapezoidal, circular, and horseshoe-shaped whorl profiles occur in succession.

Phylogeny

The origin of the subfamily Gattendorfiinae (and the entire family Gattendorfiidae ) has not yet been satisfactorily clarified. This is at least partly owing to the fact that in the lowest part of the Gattendorfia Limestone several species of Gattendorfia ( G. subinvoluta , G. rhenana , G. immodica ) and Gattenpleura ( G. pfeifferi ) with quite complex morphology cryptically appear almost simultaneously. Two hypothesis may be discussed here:

(1) An origin from the subfamily Prionoceratinae : Vöhringer (1960: 179) thought that it is possible that Gattendorfia could have originated from Mimimitoceras varicosum via Kornia sphaeroidalis . This assumption is mainly based on the interpretation that the presence of shell constrictions is an important character. This hypothesis could be strengthened by another argument not mentioned by Vöhringer – the low coiling rate in the gattendorfiids. This hypothesis states that the main morphological novelty in the Gattendorfiinae is the widely umbilicate juvenile whorl.

(2) An origin from the subfamily Acutimitoceratinae : this hypothesis was suggested by Korn (1986); the concept was taken over by Kullmann (2009) in the subdivision of the Prionoceratoidea . The hypothesis is based on the assumption that the evolute juvenile whorls are an important character and were passed from Stockumites to Gattendorfia . This hypothesis could be supported by the fact that several species of Gattendorfia have rounded trapezoidal whorl profiles in the juvenile whorls similar to, for example, the stratigraphically early species Stockumites hilarum .

The intra-subfamily phylogenetic relationships also do not appear clear. The common character of the rursiradiate growth lines in almost all representatives of the Gattendorfiinae can be taken as evidence that it is at least a monophyletic unit. There may be several evolutionary lineages, (1) Gattendorfia – Zadelsdorfia , (2) Gattendorfia – Kazakhstania , (3) Gattenpleura – Weyerella and (4) Gattenpleura – Hasselbachia . This includes the hypothesis that Weyerella with the genuinely simple conch morphology and faint ornament is not the ancestor of the obviously much more complex Gattenpleura , but on the contrary is the descendent of Gattenpleura and characterised by simplification of conch and ornament. The origin of Gattenpleura remains unclear.

Stratigraphic occurrence

Species of the subfamily Gattendorfiinae are known from strata of the Early and Middle Tournaisian. Gattendorfia , Gattenpleura and Hasselbachia are restricted to the Early Tournaisian, while Zadelsdorfia , Weyerella and Kazakhstania also extend from the Early Tournaisian into the Middle Tournaisian.

Geographic occurrence

Species of the Gattendorfiinae are nearly global in distribution; they have been described from the Rhenish Mountains ( Schmidt 1924, 1925; Vöhringer 1960; Korn 1994, 2006; Becker 1997; Korn & Weyer 2003; Korn & Vöhringer 2004; Becker et al. 2021), Thuringian Mountains ( Schindewolf 1924, 1926a, 1952; Pfeiffer 1954; Weyer 1976, 1977; Bartzsch & Weyer 1982, 1986, 1987, 1988a, 1988b, 1996), Upper Franconia ( Münster 1839b; Schindewolf 1923), Silesia ( Weyer 1965; Dzik 1997), the Carnic Alps ( Korn 1992b; Schönlaub et al. 1992), the Montagne Noire ( Korn & Feist 2007). They are also known from Anti-Atlas (Korn et al. 2002; Bockwinkel & Ebbighausen 2006; Ebbighausen & Bockwinkel 2007), western Algeria ( Conrad 1984; Ebbighausen et al. 2004), the South Urals ( Popov 1975; Popov & Kusina 1997), Karaganda ( Librovitch 1940) and Mongolia ( Kusina & Lazarev 1994). In China they were described from Xinjiang ( Sheng 1984; Ruan 1995), Tibet ( Liang 1976) as well as Guizhou ( Ruan 1981) and in the United States from Montana ( Gordon 1986), New Mexico ( Gordon 1986), Iowa ( Furnish & Manger 1973), Indiana ( Smith 1903; Gutschick & Treckman 1957), Kentucky ( Work & Mason 2005, 2009), Michigan ( Miller & Garner 1955), Missouri ( Miller & Collinson 1951) and Ohio ( Smith 1903; Manger 1971).