Perlomyia cantalensis, Boderau & Ngo-Muller & Nel, 2024

Boderau, Mathieu, Ngo-Muller, Valerie & Nel, André, 2024, First representatives of the stonefly genus Perlomyia and the beaded lacewing genus Isoscelipteron from the Upper Miocene of France (Plecoptera: Leuctridae and Neuroptera: Berothidae), with biogeographical considerations, Zootaxa 5481 (1), pp. 131-140 : 132-136

Perlomyia cantalensis sp. nov.

urn:lsid:zoobank.org:act:A122D4A3-1FED-400A-863F-D107AB4D4A6C

Figs 1–4

Material. Holotype IF-STR-0104 (a complete body, with leg fragments, a forewing and a broken hind wing, which is not surprising because these insects are especially fragile), provisionally housed in the Muséum National d’Histoire Naturelle , Paris, France.

Etymology. Named after the Cantal department of France.

Locality and horizon. Latest Miocene, diatom paleomaar, Sainte-Reine (quarry of Foufouilloux, Virargues village), near Murat, Cantal, France.

Diagnosis. Wings infuscate; hind wing ra-rp crossvein located slightly basad to fork of RP; cerci without visible expansion, sternite IX elongate but relatively short, not extending below the male genitalia.

Description. Body dark brown, 6.5 mm long; wings infuscate. Head 0.8 mm long, 0.6 mm wide; antennae and mouthparts not discernable. Thorax 1.5 mm long, 1.2 mm wide; fragments of legs unpreserved except for a complete detached leg, showing second tarsomere shorter than first and third tarsomeres. Forewing 8.0 mm long, 2.3 mm wide; area between ScP and costa 0.1 mm wide; ScP 4.1 mm long, simple; R/RA straight; RP separating from RA 1.2 mm from wing base, at same point where M separates from R; RP with two long straight branches, separating 2.8 mm distad of base of RP, without crossvein in-between; crossvein between RA and RP aligned with distal vein between ScP and RA; M forked 2.0 mm from its base, without crossvein between its branches; branches of RP and of M anteriorly curved; eight oblique crossveins between M and CuA; 10 oblique crossveins between CuA and CuP; CuA simple, nearly straight with a weak posterior curve at its apex; branches of PCu sigmoidally curved, with a very small basal cell in-between, anal vein very short. Hind wing 6.3 mm long, ca. 1.9 mm wide; ScP 2.5 mm long, simple; RP with two long simple branches; ra-rp crossvein located slightly basad to fork of RP; crossvein m-cu distad of fork of Cu; three anal veins. Abdomen 4.2 mm long, 0.8 mm wide; cerci without visible expansion, sternite IX elongate but relatively short, not extending below the male genitalia.

Remark. The pattern of the forewing venation of this fossil is nearly identical to that of the extant genus Leuctra Stephen, 1836 , supporting an attribution to the family Leuctridae . More precisely, it belongs to the Leuctridae because of the following characters: needle-like habitus, absence of gills, absence of X-patterned crossveins in forewings, second tarsal segment shorter than first and third segments, in forewing CuA simple, and antero-distal cell lacking a crossvein (Béthoux et al. 2015, Chen & Du 2018; Chen & Liu 2022).

The new fossil is unlikely to fit in the monogeneric subfamily Megaleuctrinae with Megaleuctra Neave, 1934 . This genus is characterized by large body size (about 15 mm) and the presence of six anal veins in hind wing, vs. only three in the new fossil ( Ham & Bae 2002).

The male sternite IX of the new fossil is strongly produced as in Perlomyia ( Ricker, 1943) . The veins RP and M of forewing with a common origin is a character of the new fossil only present in the extant genus Perlomyia (Needham & Claassen, 1925: pl. 32, fig. 5; Nelson & Hanson, 1973), unlike in Leuctra , Pachyleuctra Despax, 1929 , Calileuctra Shepard & Baumann, 1995 , Paraleuctra Hanson, 1941 , Pomoleuctra Stark & Kyzar, 2000 , Zealeuctra Ricker, 1952 , Moselia Ricker, 1943 , Despaxia Ricker, 1943 , Rhopalopsole Klapálek, 1912 , Tyrrhenoleuctra Consiglio, 1957 (replacement name for Strobiella Klapálek, 1901), † Baltileuctra Chen, 2018 , † Euroleuctra Chen, 2018 and † Palaeopsole Caruso & Wichard, 2011 (all from Baltic amber, Eocene) ( Klapálek 1912; Ricker 1943, 1952; Consiglio 1956, 1957; Berthélemy 1968; Shepard & Baumann 1995; Shimizu 2000; Stark & Kyzar 2000; Caruso & Wichard 2011; Chen 2018a,b).

Furthermore, the new fossil strongly differs from Pomoleuctra in the structure of the branches of PCu that are sigmoidally curved and with a very small basal cell in-between in the new fossil vs. simply posteriorly curved with a broad cell in-between in the latter ( Stark & Kyzar 2000). Calileuctra differs from the new fossil in the branches of PCu distally fused and not sigmoidal and in the presence of only three crossveins between M and CuA in forewing ( Shepard & Baumann 1995). Tyrrhenoleuctra and † Baltileuctra also have only three-four such veins ( Consiglio 1956). Moselia and Despaxia are excluded because the crossvein m-cu is distad of the fork of Cu in hind wing in the new fossil (vs. proximad).

In † Baltileuctra the ra-rp crossvein is located distally to the fork of RP in forewings but basal to it in hind wing, a character uncommon among Leuctridae ( Chen & Liu 2022: 652) . In the new fossil, the hind wing ra-rp crossvein is also located slightly basad to the fork of RP, while in the extant Perlomyia , the hind wing ra-rp crossvein is located opposite the fork of RP ( Nelson & Hanson 1973). † Baltileuctra has very long cerci, unlike the new fossil.

The new fossil has simple cerci, its sternite IX is relatively short, while the extant species have a longer sternite IX and/or cerci with expansions ( Frison 1936; Kawai 1967; Nelson & Hanson 1973; Zhiltzova 1974, 1975; Shimizu 2000; Sivec & Stark 2012a,b; Murányi et al. 2014; Murányi & Hwang 2017; Nakamine 2022).

Figures

FIGURE 1. Perlomyia cantalensis sp. nov., holotype IF-STR-0104. Photograph of general habitus. Scale bar = 2 mm.

FIGURE 2. Perlomyia cantalensis sp. nov., holotype IF-STR-0104. Photographs. A, forewing. B, leg. Scale bars = 2 mm (A), 1 mm (B).

FIGURE 3. Perlomyia cantalensis sp. nov., holotype IF-STR-0104. Photograph of hind wing. Scale bar = 2 mm.

FIGURE 4. Perlomyia cantalensis sp. nov., holotype IF-STR-0104. Reconstruction of terminalia.. Scale bar = 1 mm.