Orchestina parisiensis, Penney, 2007

Penney, David, 2007, A new fossil oonopid spider in lowermost Eocene amber from the Paris Basin, with comments on the fossil spider assemblage, African Invertebrates 48 (1), pp. 71-75 : 72-73

Orchestina parisiensis sp. n.

Fig. 1

Etymology: After the type locality.

Diagnosis: The main diagnostic characters of male Orchestina are the relative proportions of the palpal segments and the shape of the embolus (Wunderlich 2004). The bifid tip of the embolus and the embolus length relative to that of the bulb distinguish the new species.

Description (based primarily on holotype): Body length approximately 1.0 mm; carapace 0.54 mm long, 0.43 mm wide, domed and without the long, erect setae often observed in other fossil Orchestina . Six eyes in the segestroid position (sensu Wunderlich 2004) typical of the genus. Opisthosoma approximately 0.5 mm long, 0.4 mm wide. Femur of leg 4 (as seen in the paratype) distinctly larger than legs 1–3; all legs without spines. The pedipalp is clearly visible in the holotype: tibia 0.16 mm long, 0.10 mm high, the cymbium is small and highly setose, bulb subspherical, 0.17 mm wide, 0.11 mm high; embolus 0.07 mm long with a kink distally and with a bifid tip ( Fig. 1B ).

Holotype: PA 759, male, visible in dorsal view, opisthosoma collapsed and covered with a white emulsion as commonly observed in Baltic amber inclusions, spinnerets not visible, only third left leg present and only femur and patella can be seen but are not in a position conducive to taking measurements; there is one cyclorraphan fly syninclusion preserved directly below the holotype. FRANCE: Oise: Paris Basin, Le Quesnoy; lowermost Eocene amber.

Paratype: PA 1909, male, same data as the holotype.

Remarks: This is the first spider species to be described from French amber. Based on the palpal structure and particularly the bifid tip of the embolus, the new species is probably most closely related to O. baltica Petrunkevitch, 1942 (see Wunderlich 1981, fig. 4, 2004, figs 8k–m). However, the embolus of O. baltica is longer than the height of the bulb, whereas that of the new species is shorter. The holotype was selected based on the exceptional view of the pedipalp (the most important structure for species identification in spiders). However, in this specimen the fourth pair of legs is missing, but these are preserved in the paratype and have the thickened femur diagnostic of the genus Orchestina .

Figures

Fig. 1. Orchestina parisiensis sp. n., holotype PA 759 (lowermost Eocene amber from Le Quesnoy, Paris Basin, France): (A) dorsal view of the specimen in amber, (B) details of the body structures, dorsal view. Abbreviations: (b) bulb, (c) cymbium, (car) carapace, (e) embolus, (fe) femur, (op) opisthosoma, (pp) pedipalp, (ti) tibia. Scale bar 0.5 mm.