Eurhopalothrix, Brown & Kempf, 1961

Chaul, Júlio Cezar Mário, 2022, Redescription of Eurhopalothrix reichenspergeri (Santschi, 1923) stat. rev. (Hymenoptera: Formicidae), a Brazilian Atlantic Forest endemic species, Zootaxa 5182 (1), pp. 1-20 : 15-17

Eurhopalothrix ufv-01 (male morphospecies)

( Figs 14 , and 15 D to F)

Diagnosis. Mandible with an overall concave masticatory margin with a minute indentation near the apex which barely forms an apical tooth. Scape with strongly convex anterior margin. Compound eyes not strongly bulging. Propodeal lamella translucid and light colored. Petiole node dorsal surface smooth, posteriorly with a transverse carina.

Measurements. HW 0.48, HW 2 0.44, HL 0.51, EL 0.2, MsscmL 0.39, MsscmW 0.42, MssctmL +MssctlL 0.62, WL 0.79, WfL 2.55, PetW 0.14, PpetW 0.27, GW 0.49, G1L 0.46, CI 94 (n=1)

Description. Head. Lateral and anterior margins of clypeus forming a subrectangular anterior section of head, margin thinly translucid; anterior clypeal margin flat in full-face view; epistomal sulcus more or less straight across antennal insertions; overall clypeal shape trapezoidal. Lateral margin of head between anterolateral corner of clypeus and compound eye concave. Compound eye bulging, but not strongly. Lateral margins of head posterad the eye smoothly curving to vertex, not forming well-marked vertexal angles. Mandible masticatory margin edentate and concave. Labrum not forming prominent lobes, its apical margin apparently with simple setae. Palpal formula could not be precisely determined, either 2, 1 or 1, 1. Frontal carina bifurcated posteriorly. Malar carina linking anterior eye to lateral edge of clypeus. Thin lamellate carina present ventrolaterally on head, from hypostomal tooth to about half the compound eye level. Frontal lobe dorsally protruded, separated from posterior clypeal margin by an oblique carina. In posterior view, scape bent, anterior edge strongly convex; scape length about 1.5x that of pedicel; antennomeres 3–13 with decumbent small, simple setae; antennomeres 3–12 subequal in length, only getting slightly shorter posteriorly; apical antennomere the longest. Dorsum of head evenly reticulate, without rugulae or carinae except for those described above. Mesosoma. Notauli deep anteriorly, with a few transverse carinae, posteriorly much shallower. Mesoscutum reticulate. Parapsidal lines and transcutal line well-marked. Scutoscutellar suture deep. Scutellum reticulate with superimposed rugulae, roughly trapezoidal, but with bilobed posterior margin. Pleural sculpturing reticulate, except for smooth upper portion of lower mesopleuron, lower portion of upper mesopleuron and middle section of lower metapleuron. Mesopleuron separated from metapleuron by thin suture; upper metapleuron separated from lower metapleuron and from lateral propodeum by deep sulci; lower metapleuron merged and lower lateral propodeum not separated by sulcus. Propodeal spiracle raised from cuticle. Propodeal spine triangular, subtended by thin lamella, both somewhat spongious and translucid. Wings hyaline. Metasoma. Petiole node in profile with poorly defined anterior and dorsal margins and well-defined, carinated, dorsal and posterior margins; dorsal surface of node smooth. Subpetiolar process small, finger-like, anteroventrally directed. Postpetiole tergite mostly smooth, except for reticulation posterolaterally; sternite with a pair of lateral simple, flexuous setae (longer than the pair present in workers). Gaster first tergite and sternite anteriorly carinated, gaster entirely smooth and shiny.

Pilosity. Body covered mostly on simple and flexuous setae, some only slightly thicker with frayed apex, never developed as spatulated or remiform. The thicker setae form defined pairs in between eye and frontal carina (1 pair), medially on vertex (at least 2 pairs), laterally on occipital carina (1 pair), some on the mesoscutum and mesoscutellum, and laterally on the postpetiole (1 pair).

Color. Overall dark brown to black, except for dark brown mandibles and antennae (mostly) and light brown legs (except for coxae which are darker) and apex of antennae.

Comments. This male morphospecies occurs in Viçosa, Minas Gerais, Brazil, where three Eurhopalothrix species are known by the females: E. bruchi , E. reichenspergeri and E. spectabilis . Eurhopalothrix ufv-01 is likely the male of E. spectabilis for sharing with the females the following traits (although not manifested in the male in the exact same way as in the females): labral apical margin without prominent lobes; scape lobe relatively large; propodeal lamella translucid; and posterior margin of petiole node with a marked carina.

Eurhopalothrix ufv-01 differs from the male of E. reichenspergeri by the concave masticatory margin of the mandible, as opposed to a marked toothed margin; a translucid, very thin border of the clypeus, as opposed to a thicker (still translucid) band along the clypeal margin; a more strongly lobate anterior scape margin; the compound eyes not bulging conspicuously; the vertexal corners slightly less pronounced; a smooth rather than reticulate lower metapleuron; a more developed and whitish/spongious propodeal lamella rather than a thinner and darker one; the ventral petiole margin more straight as opposed to having a wavy margin; the petiolar node posteriorly transversely carinated; the postpetiole pair of posterolateral stand setae thinner than in E. reichenspergeri , which is strongly spatulate ( Fig. 15 ).

There are no images of the male of E. gravis , which was described by Mann (1922). Through the description alone, a trait which can be highlighted as an important difference between E. gravis and E. reichenspergeri males is the mandible having a concave masticatory margin (“blades strongly concave” in Mann, 1922) in the former as opposed to dentate in the latter.

The male of E. floridana Brown & Kempf, 1960 has been described ( Deyrup et al.,1997) and images of one specimen are available on Antweb (CASENT0103905, images by April Nobile). It has a concave masticatory margin, barely forming an apical tooth (similar to Eurhopalothrix ufv-01); the vertexal margin is without marked vertexal corners (similar to Eurhopalothrix ufv-01); it lacks thickened setae on most of the body, but it does have a pair of spatulate setae laterally on postpetiole. The only smooth pleural regions are the lower and upper mesopleura (similar to E. reichenspergeri ). It lacks a propodeal spine (differing from E. gravis , E. reichenspergeri and Eurhopalothrix ufv-01 in that respect), but has a thin propodeal lamella. It apparently has a poorly developed subpetiolar process and the petiole node does not have a posterior transversal carina (similar to E. reichenspergeri ). The wings are slightly infuscated (similar to E. gravis and E. reichenspergeri ). It seems to be overall smaller than E. reichenspergeri and similar in size to Eurhopalothrix ufv-01, as the size of forewing indicates (2.32–2.45 mm in E. floridana).

Examined material. BRA, MG, Viçosa , Mata do Paraíso, -20.79559 -42.85886, 21-31.iii.2017, Aerial Malaise (0.7– 1.2 m), Jesus, R. (1 male, ANTWEB1038061) [CELC] .

Figures

FIGURE 14. Eurhopalothrix ufv-01 (ANTWEB1038061), the putative male of E. spectabilis. A, profile view of body; B, dorsal view of the body; C, detail of mandibles in anterodorsal view; D, mesothorax in dorsal view. Scale bars are 0.1 mm. Abbreviations (according to Boudinot, 2015): pl, parapsidal line; tscl, transcutal line; sss, scutoscutellar suture.

FIGURE 15. Comparison of full-face view of head (A and D), mesosoma profile (B and E) and propodeum, petiole and postpetiole (C and F) between males of Eurhopalothrix reichenspergeri and Eurhopalothrix ufv-01. A–C, E. reichenspergeri (UFV-LABECOL-010764); D–F, Eurhopalothrix ufv-01 (ANTWEB1038061). Scale bars are 0.1 mm. Arrowheads indicate characters which differ between the species (see discussion under Eurhopalothrix ufv-01 comments).