Dombaritinae (Kullmann, 2009)

Titus, A. L., Korn, D., Harrell, J. E. & Lambert, L. L., 2015, Late Viséan (late Mississippian) ammonoids from the Barnett Shale, Sierra Diablo Escarpment, Culberson County, Texas, USA, Fossil Record 18 (2), pp. 81-104 : 94

Subfamily Dombaritinae (in Kullmann et al., 2007)

Subfamily diagnosis: Delepinoceratidae with advanced, moderately wide external lobes (usually between 0.60 and 0.90, measured at half height, of the external lobe depth), and median saddles with a height of 0.50 to 0.75 of the external lobe depth. External lobe Y-shaped and undivided.

Included genera:

Choctawites n. gen.

Lusitanoceras Pereira de Sousa, 1923

Revilloceras Wagner-Gentis, 1980

Dombarites Librovitch, 1957

Proshumardites Rauser-Tschernoussowa, 1928 Deleshumardites Kullmann, 2007

Discussion: Distinctive Late Viséan to early Serpukhovian goniatitids with advanced lobes (especially with broader, more deeply divided external lobe) have an almost cosmopolitan distribution ( Librovitch, 1957; Gordon, 1965; Ruzhencev and Bogoslovskaya, 1970, 1971; Drahovzal and Quinn, 1972; Wagner-Gentis, 1980; Webster et al., 1984; Korn et al., 1999; Nikolaeva and Konovalova, 2005; Klug et al., 2006). Until recently, it was thought that this morphological complex formed an essentially monophyletic clade that dispersed during the Late Viséan, evolving from the advanced goniatitid Lusitanoceras ( Korn, 1988, 1997b; Kullmann, 2009a). Cross sections of various specimens belonging to Lusitanoceras were shown by Kullmann and Pitz (1980), Kusina (1987), Korn (1988, 1997b), Kusina and Yatskov (1999) and Nikolaeva and Konovalova (2005); all sections possess a rather long subevolute juvenile stage.

Nikolaeva and Konovalova (2005) figured cross sections of a series of specimens from the Urals that were all referred to as the genus Dombarites by Ruzhencev and Bogoslovskaya (1971) and concluded that the shapes of the early whorls in this are very different to those of the genus Lusitanoceras . Consequently, Nikolaeva and Konovalova (2005) postulated that Dombarites sensu stricto did not evolve from Lusitanoceras , but directly from the genus Goniatites . Indeed, the figured cross sections of Dombarites with subinvolute inner whorls suggest that the umbilical width in the inner whorls are more similar to Goniatites ; however, one has to keep in mind that there is no reason to assume that evolutionary pathways always proceed in the same trend (e.g. from involute to evolute inner whorls); Dombarites , with its less widely umbilicate inner whorls may also have been derived from more evolute forms. Furthermore, the suture lines of all of the genera assembled in the subfamily Dombaritinae are very similar in great detail, speaking for very close relationships and obviously ruling out homoplasy.

A more detailed subdivision of the various forms often assembled in the genus Dombarites requires the separation of genera on the base of morphology of the inner whorls, ornament and suture line details ( Table 6 ). For this reason we describe the new genus Choctawites to accommodate the North American species “ Goniatites choctawensis Shumard, 1863 ”, “ G. kentuckiensis Miller, 1889 ” and “ G. cumminsi Hyatt, 1893 ” and revive the genus Revilloceras Wagner-Gentis, 1980 for superficially similar species known from the Cantabrian Mountains of Spain and the Anti-Atlas of Morocco.