Uchtospirifer Ljaschenko, 1957

Sokiran, Elena V., 2006, Early-Middle Frasnian cyrtospiriferid brachiopods from the East European Platform, Acta Palaeontologica Polonica 51 (4), pp. 759-772 : 762-763

Genus Uchtospirifer Ljaschenko, 1957

1957 Uchtospirifer Ljaschenko gen. nov.; Ljaschenko 1957: 885.

1958 Uchtospirifer Ljaschenko, 1957 ; Ljaschenko 1958: 148.

1959 Uchtospirifer Ljaschenko, 1957 ; Ljaschenko 1959: 247.

1973 Uchtospirifer Ljaschenko, 1957 ; Ljaschenko 1973: 88.

1973 Timanospirifer Ljaschenko gen. nov.; Ljaschenko 1973: 92. 1973 Nordispirifer Ljaschenko gen. nov.; Ljaschenko 1973: 104.

1973 Clivospirifer Ljaschenko gen. nov.; Ljaschenko 1973: 108.

1973 Acutella Ljaschenko gen. nov.; Ljaschenko 1973: 119.

Emended diagnosis. —Moderately to strongly inflated shells with short hinge and rounded cardinal extremities; delthyrium covered by deltidium except for triangular opening at the base of delthyrium; dorsal fold and ventral sulcus variably developed; costate ornamentation with closely spaced and flattened costae; costae on fold and sulcus variably developed or absent; micro−ornamentation consists of sub−radial capillae converging on top of costae and tubercles; ventral interior with dental plates, with or without delthyrial plate. Differs from Cyrtospirifer by short hinge, rounded cardinal extremities, and micro−ornamentation (emended after Ljaschenko 1957, 1959, 1972).

Remarks.—The number of spiriferid taxa described by Ljaschenko (1959, 1973) from the Devonian of South Timan was reduced considerably after substantial revisions by Talent and Gratsianova (1988) and Oleneva (2003, 2004). In particular the genera Timanospirifer , Nordispirifer , Clivospirifer , and Acutella were reassigned as junior synonyms of Uchtospirifer because of similar shell morphology and micro−ornamentation.

Talent and Gratsianova (1988) considered Mennespirifer as synonym of Cyrtospirifer . Recently Oleneva (2006) recognized Mennespirifer as a junior synonym of Komispirifer although Ljaschenko (1959, 1973) considered the former as belonging to uchtospiriferins.

The diagnostic external characters of uchtospiriferins include rounded cardinal extremities and peculiar micro−ornamentation (see Ljaschenko 1973; Oleneva 2003, 2004). Noteworthy is also a weakening or complete disappearance of sinal costae in some representatives of the subfamily (e.g., in Uchtospirifer angulosus , U. timanicus , and U. nalivkini ). These characters distinguish them from Cyrtospirifer and Cyrtiopsis . Moreover, the latter have foramen at the top of the deltidium. Therefore, Ljaschenko (1973) distinguished uchtospiriferines from other Cyrtospiriferidae .