Oncopareia lunata (Fritsch & Kafka, 1887)
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publication ID |
https://doi.org/ 10.26879/1190 |
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persistent identifier |
https://treatment.plazi.org/id/FA348794-FFA9-7A4D-FF11-EDBA5099CFB5 |
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treatment provided by |
Felipe |
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scientific name |
Oncopareia lunata |
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Oncopareia lunata (Fritsch in Fritsch and Kafka, 1887)
Figure 9A–D View FIGURE 9
1887 Nymphaeops? lunatus Fritsch in
Fritsch and Kafka, p. 35, pl. 5, fig. 6.
1929 Nymphaeops? lunatus ; Glaessner,
p. 279.
1941 Oncopareia lunatus (Fritsch in
Fritsch and Kafka); Mertin, p. 180.
2000a Oncopareia? lunatus (Fritsch in
Fritsch and Kafka); Tshudy and Sorhannus, pp. 481, 484-appendix 1.
2010 Oncopareia lunatus (Fritsch in
Fritsch and Kafka); Schweitzer et al.,
p. 32.
Material examined. Holotype, NM O3473 , in the palaeontological collections of the National Museum in Prague.
Diagnosis. Oncopareia with arcuate (concave-up) intercervical groove extending toward upper part of cervical groove.
Description. This species is known by a single specimen preserving part of a dorsoventrally flattened cephalothorax (without rostrum and anterior region) and the pleon in dorsal aspect. The pleon itself is connected to the cephalothorax. Long postcervical groove intersects dorsal median line slightly posteriorly to mid-length on carapace; as combined branchiocardiac-postcervical groove, extending anteroventrally to hepatic groove; then, bifurcating at third-height of carapace and as arcuate intercervical groove curving toward, but not reaching, the level of top of cervical groove. Branchiocardiac groove absent posteriorly and beginning as branchiocardiac-postcervical groove; after bifurcating extending ventrally to join semicircular hepatic groove. Cervical groove well incised, short. Anteroventral part of cephalothorax, in region of antennal and inferior grooves, not preserved. Pleura short; pleonal terga wide, convex with a lateral carina at tergum-pleuron boundary.
Remarks. Mertin (1941) referred this species to Oncopareia based on the short pleura; he did not comment on the cephalothorax grooves. Tshudy (1993, pp. 300–301), based on the published illustration, assigned the single specimen with Oncopareia -like pleon to “ Oncopareia ?”; the uncertainty was based on the urogastric groove on the cephalothorax, which is unknown in Oncopareia . Personal re-examination of the type material by one of us (MKV) confirmed the attribution of the species to Oncopareia . In this respect, it should be stressed that the original restoration of this form (Fritsch and Kafka, 1887, pl. 5, fig. 6) does not fully correspond with the original specimen. Fritsch pencil marked the specimen to highlight morphological features, and, as a result, two distinct transverse grooves crossing the dorsal midline of the cephalothorax appeared in his drawing. These grooves look to be the urogastric and postcervical grooves, the former being known in several nephropid genera, but not in Oncopareia . However, after washing the specimen, it turned out that Fritsch marked an extra line (i.e., a potential urogastric groove) on this particular specimen. In actual fact, there is only one transverse groove crossing the dorsal midline, the postcervical groove. Thus, caution must be exercised when dealing with Fritsch’s taxa on the basis of published drawings only.
Oncopareia lunata differs from O. bredai in having a considerably shorter cervical groove, a more arcuate intercervical groove oriented toward the level of the top of the cervical groove. In addition, it lacks a posteriorly defined branchiocardiac groove. In view of the fact that O. lunata is incompletely known (i.e., lacking the anterior region of the cephalothorax and chelipeds), further comparison with O. bredai is not possible.
Range and occurrence. The occurrence of O. lunata is so far limited to shallow-marine marlstones of the Bílá Hora Formation (lower–middle Turonian) in the Prague area, Czech Republic.
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