Aeger tipularius ( Schlotheim, 1822 )

Odin, Giliane P., Charbonnier, Sylvain, Devillez, Julien & Schweigert, Günter, 2019, On unreported historical specimens of marine arthropods from the Solnhofen and Nusplingen Lithographic Limestones (Late Jurassic, Germany) housed at the Muséum national d’Histoire naturelle, Paris, Geodiversitas 41 (17), pp. 643-662 : 645

Aeger tipularius ( Schlotheim, 1822) ( Fig. 1 A-C)

DIAGNOSIS (from Schweigert et al. 2016). — Very short smooth rostrum; Mxp3 extremely long, with movable spines; chelate P1-P3; P1-P2 bearing long movable spines; P3 with spiny chelae; achelate P4-P5 and spineless; P3 slightly larger than P1-P2; well-developed pleopods; uropodal exopod with rounded diaresis.

STUDIED MATERIAL. — Charbonnier & Garassino (2012) listed seven specimens. Careful examination leads us to re-identify some of them. Three specimens, MNHN.F.A33509 (Solnhofen), B13443 (Eichstätt), MNHN.GG.2004/8072 (unknown locality), are maintained as A. tipularius , while four others are attributed to Aeger spinipes ( Desmarest, 1817) , A. insignis ( Oppel, 1862) , and Acanthochirana cordata ( Münster, 1839) .

COMMENTS

Our assignation is based on the very short and smooth rostrum. The carapace groove pattern typical of Aeger – with a cervical groove steeply inclined, not joined to the dorsal margin but joined to the antennal groove; an oblique and sinuous branchiocardiac groove crossing all the carapace from the posterior margin to the hepatic region; and a hepatic groove joined anteriorly to the cervical groove and posteriorly to the branchiocardiac groove (see diagnosis in Charbonnier et al. 2017: 36) – is particularly visible on specimen A33509 ( Fig. 1A, B ).

Figures

FIG. 1. — A-C, Aeger tipularius (Schlotheim,1822),specimen MNHN.F.A33509 from Solnhofen;A, natural light;B, interpretation of the carapace grooves;C, UV light; D, Aeger spinipes (Desmarest, 1817), specimen MNHN.F.B13442 from Solnhofen; E, F, Aeger insignis Oppel, 1862, specimen MNHN.GG.2004/57291 from Solnhofen; E, natural light; F, UV light. Scale bars: A, C, 1 cm; B, D, 2 cm; E, 3 cm. Abbreviations: a, branchiocardiac groove; b, antennal groove; b1, hepatic groove; e1e, cervical groove. Photographs: L. Cazes. Line drawing: G.P. Odin.