Stenocheles” parvulus Fritsch

Tshudy, Dale M., Hyžný, Matúš, Veselská, Martina Kočová & Jagt, John W. M., 2022, Taxonomic revision of the extinct clawed lobster genus Oncopareia Bosquet, 1854 (Decapoda, Astacidea, Nephropidae), Palaeontologia Electronica (a 20) 25 (2), pp. 1-31 : 24-25

“ Stenocheles” parvulus Fritsch in Fritsch and Kafka, 1887

Figure 13A–F partim 1887 Stenocheles parvulus Fritsch in Fritsch and Kafka; p. 40, pl. 3, fig. 3 [non fig. 4 = Ctenocheles fritschi Hyžný, Kočová Veselská and Dvořák, 2014 ]

partim 1929 Ischnodactylus parvulus (Fritsch in Fritsch and Kafka); Glaessner, p.

226.

1941? Oncopareia parvulus (Fritsch in Fritsch and Kafka); Mertin, p. 185, text-fig. 10g.

1969? Oncopareia parvulus (Fritsch in Fritsch and Kafka); Glaessner, p.

R459.

2010 Oncopareia parvulus (Fritsch in Fritsch and Kafka); Schweitzer et al., p. 32.

2014? Oncopareia parvulus (Fritsch in Fritsch and Kafka), Hyžný et al., p.

246, figs. 1B, 1C, 2B.

Material studied. Lectotype (designated by Hyžný et al., 2014), NM O3455 (part), and NM O9092 (counterpart).

Remarks. Mertin (1941, p. 198) expressed uncertainty regarding the generic placement of this species, but (p. 179) referred it to “? Oncopareia ”. Tshudy (1993) concluded that the two specimens upon which S. parvulus was based (see Fritsch and Kafka, 1887, pl. 3, figs. 3, and 4) represented two different taxa but was unable to refer either specimen to a known genus and assigned both to “ Stenocheles ”. Hyžný et al. (2014) restudied these two specimens and recognized them as belonging to separate taxa, representing two entirely different infraorders. The heterochelous specimen NM O3456 (Fritsch and Kafka, 1887, pl. 3, fig. 4) became the holotype of Ctenocheles fritschi and the isochelous specimen NM O3455 (part) and NM O9092 (counterpart) (Fritsch and Kafka, 1887, pl. 3, fig. 3) was designated lectotype of S. parvulus (=? Oncopareia parvulus sensu Hyžný et al., 2014 ). A new re-examination of the material by one of us (MKV) shows a very poorly preserved specimen with some portions being drawn onto the fossil ( Figure 13A ). The specimen not only does not correspond to details presented in the illustration provided by Fritsch and Kafka (1887, pl. 3, fig. 3), but also does not preserve sufficient taxonomically important characters to define the species. Moreover, its assignment to Oncopareia or Ctenocheles is highly dubious. The palms of S. parvulus are more elongate than is characteristic of either Ctenocheles or Oncopareia . The finger/palm length ratios on both specimens are smaller than on Ctenocheles , and much smaller than on Oncopareia . Importantly, the genus Stenocheles cannot be used for S. parvulus , because the type species of Stenocheles is Stenocheles esocinus (as designated by Glaessner, 1969), which is here reassigned to Oncopareia , thereby making Stenocheles a junior subjective synonym of Oncopareia (see above). Therefore, we refer S. parvulus to “ Stenocheles ” and consider “ Stenocheles” parvulus a taxon of unknown affinities (incertae sedis). The classification of this dubious taxon at the infraordinal level is here considered only a matter of convenience rather than an assignment based on important characters.

Range and occurrence. Upper Cretaceous, lower–middle Turonian (Bílá Hora Formation) of Bílá Hora (‘Weissenberge’) in Prague, Czech Republic (Fritsch and Kafka 1887, p. 40).

AXIIDEA de Saint Laurent, 1979

CTENOCHELIDAE Manning and Felder, 1991

Genus Ctenocheles Kishinouye, 1926

Type species. Ctenocheles balssi Kishinouye, 1926 , by monotypy.

Figures

FIGURE 13. “Stenocheles” parvulus Fritsch, in Fritsch and Kafka, 1887; lectotype from the lower–middle Turonian (Bílá Hora Formation) in Prague, Czech Republic. A–C, Part of the specimen (NM O3455) under various light conditions. D–F, Counterpart of the same (NM O9092), including the historical cast (D).