Rogeryon oppeli ( Woodward, 1866 ) Audo & Schweigert & Charbonnier & Haug Umr Cnrs & Lmu, 2017

Audo, Denis, Schweigert, Günter, Charbonnier, Sylvain & Haug, Joachim T., 2017, Systematic revision and palaeobiology of Rosenfeldia triasica and Rogeryon oppeli gen. et comb. nov. (Eucrustacea, Polychelida), European Journal of Taxonomy 367, pp. 1-23 : 11-15

publication ID	https://doi.org/ 10.5852/ejt.2017.367
DOI	https://doi.org/10.5281/zenodo.3852220
persistent identifier	https://treatment.plazi.org/id/03813959-FFF8-FFA9-FE4E-FC40FC8DF9F6
treatment provided by	Carolina
scientific name	Rogeryon oppeli ( Woodward, 1866 )
status	gen. et comb. nov.

Treatment

Rogeryon oppeli ( Woodward, 1866) gen. et comb. nov.

Figs 2M View Fig , 4–6 View Fig View Fig View Fig

Eryon oppeli Woodward, 1866: 500 , pl. 24, fig. 4.

Eryon oppeli – Woodward 1881: 529; 1911: 307. — Balss 1924: 175. — Glaessner 1929: 166.

Rosenfeldia oppeli – Schweigert 2004a: 70; 2004b: 329; 2015: 273. — Schweigert & Frattigiani 2005a: 198; 2005b: 328. — Garassino & Schweigert 2006: 30. — Schweitzer et al. 2010: 43. — Feldmann et al. 2013 a: 3, fig. 2.4. — Audo et al. 2016: 13, figs 1h–k.

Material examined

Holotype

GERMANY: Häberlein coll., NHMUK 44886 About NHMUK ( Fig. 4 View Fig A–B).

Other material

GERMANY: 6 other known specimens: SMNS 70102 (U. Resch coll., Fig. 4D View Fig ), SMNS 66004 ( R. Frattigiani coll., Fig. 5 View Fig A–C), SMNS 65545 ( R. Frattigiani coll., Fig. 5D View Fig ), SMNS 66004/2 ( R. Frattigiani coll. Fig. 5E View Fig ); one specimen from K. and H. Schumacher pers. coll., without number ( Fig. 4D View Fig ); one specimen from U. Resch pers. coll. JMS 118 ( Fig. 4C View Fig ).

Type locality

GERMANY: “Solnhofen”, Bavaria, Germany.

Type age

Late Jurassic, Early Tithonian, Hybonotum ammonite biozone (after Schweigert 2007b).

Diagnosis

See genus.

Description

SHAPE OF CARAPACE. Extremely thin exoskeleton; pear-shaped cephalothorax in outline in dorsal view, longer than wide, wider in its anterior half; very narrow and rather shallow frontal margin; side of frontal margin (anterolateral angle) forming a long spine; smooth lateral margin cut by ocular, cervical and postcervical incisions; deep ocular incision, hemicircular, opening laterally and closed ventrally; long anterolateral margin, almost straight, oblique compared to longitudinal axis; small and shallow cervical and postcervical incisions, both opening in the anterior half of lateral margin; straight mediolateral margin, distinctly shorter than anterolateral margin; triangular posterolateral angle, projecting along s1; posterior margin concave, distinctly wider than anterior margin.

CARAPACE GROOVES AND CARINAE. Cervical groove extending from cervical incision, strongly marked medially and near lateral margin, probably cutting median line, and medially shallower between these two areas; postcervical groove longer than one third of carapace width, not connected to cervical groove, strongly marked from postcervical incision toward median line; shallow branchiocardiac groove extending obliquely in the posterior half of carapace; dorsal carinae (branchial, postorbital, median carinae) not visible; raised submarginal carina, extending ventrally parallel to lateral margin in the first half of carapace.

PLEON AND TELSON. Pleon slightly shorter and one-half width of carapace; pleonite 1 poorly preserved, shorter than others; s2–s6 with terga crossed by two transverse grooves converging medially and by an axial carina placed posteriorly to anterior transverse groove and cutting posterior transversal groove to join with posterior margin; s3–s5 tergopleura with concave lateral margin, which appears hooked; s2–s5 tergopleura with a small anterior process articulating with a small notch in the preceding pleonite; sharp s6 tergopleuron; telson rounded distally, with finely serrated margins, a pair of serrated longitudinal carinae and, possibly, a median carina.

EYE AND CEPHALIC APPENDAGES. Large spherical eye with hexagonal ommatidia; mandible with a massive triangular coxal body and a subtriangular incisor process, the edge of which forms several teeth (poorly preserved); other cephalic appendages too poorly preserved to be described.

THORACIC APPENDAGES. Third maxilliped with a hemicircular ischium and short following podomeres; median margin of third maxilliped ischium inner margin serrated with numerous thin spines (crista dentata); stocky pereiopods, decreasing in size from the first to the last, with slightly stocky and curved dactylus and pollex; P1 only slightly larger than P2.

PLEONAL APPENDAGES. Elongated petasma (modified pleopods 1 of male), poorly preserved; uropods with a short basipodite carrying a rounded endopod and a rounded exopod with a small spine on outer margin; uropodal endopod and exopod both strengthened by a longitudinal carina; uropodal exopod with no visible diaeresis.

ORNAMENTATION. Carapace covered with thin, rounded tubercles.

Occurrence

Early Tithonian of southern Germany.

Comments

All available specimens seem to differ from each other by the shape of their carapace. The shapes of both sides of the carapaces do not often match. These differences are undoubtedly due to the thinness of the carapace, which was deformed easily during fossilisation. In addition, due to its carapace which is probably divided across its median line, the specimen SMNS 70102 ( Fig. 4D View Fig ) is likely an exuvia; it shows a deformation possibly consistent with that interpretation. Due to these constraints, we base our reconstruction ( Figs 2M View Fig , 6 View Fig ) of the outline of the carapace on specimens that seemed the less deformed such as SMNS 65545 ( Fig. 4E View Fig ) and SMNS 66004 ( Fig. 5 View Fig ).