Paleonematus jarzembowskii, NEL, 2022

NEL, ANDRÉ, 2022, The oldest fossil of the sawfly subfamily Nematinae (Hymenoptera: Tenthredinidae) from the Paleocene of Menat (France), Palaeoentomology 5 (3), pp. 289-293 : 290-291

Paleonematus jarzembowskii sp. nov.

( Fig. 1 )

urn:lsid:zoobank.org:act:BA215226-6917-472B-9FCC-07756519D192

Material. Holotype MNT Nel 4296 (a forewing and a hind wing attached to a fragment of the thorax), deposited in the “Musée de Paléontologie de Menat”¸ Menat, Puy-de-Dôme, France.

Etymology. Named in honor of my friend and colleague Edmund Jarzembowski. The specific epithet is treated as a noun in a genitive case.

Diagnosis. As for the genus.

Type locality and horizon. New quarry, Menat , Puyde-Dôme , France; Middle Paleocene, Menat Basin .

Description. Imprint of one complete forewing and one hind wing without trace of coloration. Forewing 9.8 mm long, 3.3 mm wide with only basal part of anal area missing; costal vein not swollen at apex; no vein Sc; a crossvein 2rrs; cell 2R1 smaller than cell 3R1; pterostigma broad; vein M separating from Cu at 3.2 mm of wing base; basal part of M straight, ending in R very close to origin of Rs+M, thus length of vein R between junctions with veins M and Rs+M shorter than first sector of Rs; main axis of vein M and that of 1m-cu subparallel; vein R not deviated between junctions of M and Sc; distance between junctions of veins M with M+Cu and those of Rs+M with R only 1.3 times length of 1m-cu; Vein 2m-cu joining cell 1Rs; cell 1M very large, 2.3 mm long, 1.7 mm wide; cell 2M 1.5 mm long, 1.2 mm wide; vein 2Cu in basal half of cell 1M; vein Rs+M weakly undulate; cell 1R1 small and narrow; cells Rs and 1Rs2 long; anal vein a ending into vein 1A 0.8 mm distad vein 2Cu; vein 2A completely outlined; vein 3A with median part not discernable but visible at wing base and at point of junction with 1A; crossvein of anal cell lacking.

Hind wing ca. 6.3 mm long, 2.3 mm wide; cell R1 elongate, closed, 4.5 mm long; basal part of Rs very long; cell 1Rs very long, closed, 1.5 mm long, 0.3 mm wide; vein 1r-m oblique, 0.6 mm long; a large medial cell 1M; an anal cell 1A.

Remarks. Piton (1940) described and figured Tenthredo primordialis from the Paleocene of Menat. The holotype (specimen 268 collection Piton) is probably lost. The exact affinities of Tenthredo primordialis are quite uncertain because of the poor original description and figure. It would have an elongate forewing cell 1Rs, unlike that of the new fossil.

Figures

FIGURE 1. Paleonematus jarzembowskii gen. et sp. nov., holotype MNT Nel 4296. A, Photograph. B, Reconstruction. Vein names in black, cell names in red. Scale bars = 1 mm.