Permocrassacus, Khramov, Shear, Mercurio & Kopylov, 2018
publication ID |
https://doi.org/ 10.4202/app.00482.2018 |
persistent identifier |
https://treatment.plazi.org/id/DD5F87D5-7F57-0050-FCB8-FD6B9BE565F0 |
treatment provided by |
Felipe |
scientific name |
Permocrassacus |
status |
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Genus Permocrassacus nov.
Etymology: In reference to the Permian period and to the encrassate ultimate legs of the species.
Type species: Permocrassacus novokshonovi sp. nov. (by monotypy); see below.
Diagnosis. —As for the type species by monotypy.
Permocrassacus novokshonovi sp. nov.
Fig. 1 View Fig .
Etymology: After Russian paleoentomologist Viktor Novokshonov (1966–2003), who studied Permian insects and performed excavations at the Tshekarda fossil site.
Holotype: VSGM 1 /viii/46 60 a, b, part and counterpart, partially preserved specimen, with a small portion of the head preserved.
Type locality: Tshekarda locality, Sylva river, Perm region, Russia.
Type horizon: Koshelevka Formation, Kungurian Stage, lower Permian.
Diagnosis.—A scolopendromorph centipede with 21 pedigerous segments and strongly modified ultimate legs much thicker than those in the other two well-described fossil species. The coxae of the ultimate legs lack pores.
Description.— The fossil preserves the entire length of the animal, including 21 pedigerous segments, some of which are partial, part of the head and the base of the right antenna. Length, 37–38 mm, greatest width about 3.1 mm at tergite 9. Head shield not preserved. Six basal segments of right antenna preserved, segments about as wide as long. Forcipules robust, claw curved. Anterior 7 pedigerous segments only partially preserved, along with probable coxae and prefemora of right legs 1–5; first leg significantly shorter and thinner than succeeding legs, legs 2–5 about four or five times thicker than leg 1. Tergites nearly uniform in size, with either straight or slightly concave, arcuate posterior margins and obvious paramedian sulci, which become less distinct posteriorly; tergite 21 with a vaguely indicated single median sulcus. Counterpart appears to preserve sterna 8–11, sterna roughly quadrate, without sulci. Legpair 20 similar in size to legpairs 1–5. Ultimate legs (legpair 21) greatly enlarged, five or six times thickness and estimated five to seven times as long as legpair 20 (more than 10 mm long), without spines or processes, preserved podomeres subequal in length and thickness, about 3 times as long as thick.
Stratigraphic and geographic range.— Type locality and horizon only.
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