Domene (Lathromene) pedroi Serrano, 2025

Domene (Lathromene) pedroi Serrano , sp. nov. ( Figs 1d View FIGURE 1 , 5 View FIGURE 5 , 6 View FIGURE 6 )

Type material. Holotype male: “ Aldeia Cimeira (Pampilhosa da Serra)\ Distrito Coimbra, Portugal \ 3.IV.2008 \ Col. A. Serrano”\\ “ A. Serrano &\ C. Aguiar leg.”\\ “ 40º 1´38.01´´ N \ 7º 58´22.61´´ W \ 635 m alt.”\\ “Holotype male\ Domene \ ( Lathromene ) \ pedroi sp. nov. \ A. Serrano det. 2024” [t] [h] [red card] GoogleMaps .

Etymology

This new species is dedicated to Pedro Martins da Silva, a master’s and doctoral student of the first author and a renowned ecologist, who would like to have been a staphylinid taxonomist, but whose scientific career path led him to study insects encoded in numbers.

Description. Microphthalmous, wingless and elongate body ( Fig. 1d View FIGURE 1 ). Coloration: body yellowish and abdomen slightly darker. Body length: 4.5 mm (male).

Head ( Figs 5a–c View FIGURE 5 ): subquadrate/orbicular, 1.1 times longer than wide (length: 0.75 mm, width: 0.68 mm), slightly wider than pronotum (1.2 times); eyes strongly reduced, with 7 ommatidia ( Fig. 5c View FIGURE 5 ); long and thin seta in supraocular, small circular depression (supraocular trichobothrium); absence of patch of minor pubescence above depression and behind eyes ( Fig. 5c View FIGURE 5 ); two dark spots in vertex marking insertions of dorsal arms of tentorium; gular sutures well defined, diverging slightly towards neck ( Fig. 5b View FIGURE 5 ); dorsal surface without any isodiametric microreticulation, with well-defined coarse and dense punctuation, similar to that of pronotum, on lateral sides and vertex; frons with sparse punctuation, almost smooth ( Fig. 5a View FIGURE 5 ); antennae almost moniliform ( Fig. 1d View FIGURE 1 ), 1.3 mm long, not reaching the base of pronotum when directed backwards; all antennomeres slightly longer than wide, the 1 st longest of all (length: 0.21 mm); 2 nd antennomere slightly longer than the 3 rd to 10 th antennomeres (1.2–1.3 times); 3 rd to 10 th antennomeres subequal and the 11 th is 1.3‒1.4 times larger than the size of each of the previous eight antennomeres; labrum deeply emarginated with 17 large setae spread over the disk and the anterior margin ( Fig. 5a View FIGURE 5 ); mandibles symmetrical with four distinct teeth in the inner edge, two of them are more pronounced; maxillary palpus with four palpomeres, second and third subequal, more than 3 times as long as broad, apical palpomere reduced and conical; internal lobe of maxilla with clusters of setae; labium with bilobed glossae, circumscribed by hairy paraglossae; labial palpus with three palpomeres, the 2 nd being the longest and more robust, and the 3 rd the thinnest.

Pronotum ( Fig. 5d View FIGURE 5 ): 1.2 times longer than wide (length: 0.72 mm, width: 0.59 mm), slightly narrower than head, widest anteriorly and distinctly tapering posteriad; anterior angles weakened, posterior angles marked but largely obtuse; basal margin well defined; punctuation similar to that of head, evenly distributed except for a smooth midline ranging from the anterior to the posterior parts; absence of any middle sulcus, interstices without microsculpture.

Elytra ( Fig. 5e View FIGURE 5 ): 1.4 times wider than long (length: 0.43 mm, width: 0.59 mm), approximately 0.6 times shorter than head or pronotum [elytra length/head length: 0.57, elytra length/pronotum length: 0.60); only slightly narrower than head (0.9 times) and as wide as pronotum (0.59 mm); flat in dorsal view; humeral angles obsolete; lateral margins parallel; surface with coarse, rugose and wrinkled punctuation. Wingless.

Abdomen ( Figs 5f–h View FIGURE 5 ): Maximum width at segment VI (0.69 mm), 1.2 times wider than elytra; tergites III‒VII with fine and dense punctuation within a polygonal microsculpture of transverse meshes, these more pronounced in the intersegmental membranes; sternite III with a middle carina (intercoxal carina) in the first half ( Fig. 5f View FIGURE 5 ) surrounded in both sides by a slight depression to accommodate the resting metacoxae; sternites III‒VI with fine and dense punctuation within a microsculpture of transverse meshes, substituted by irregular rows of scale-shaped microtrichia anteriad near the intersegmental membranes and by regular posteriad quadrate meshes. Sternite VII without any median impression posteriorly; sternite VIII slightly transverse, distinctly and circularly excised at posterior margin surrounded by a small glabrous area, surface with a microsculpture of polygonal meshes ( Fig. 5g View FIGURE 5 ); sternite IX slightly arcuate apically; genital segment in ventral view as in figure 5h.

Legs: Long and slender; forelegs with antennal cleaning organ following the general pattern of the genus (e.g. see Figs 2e–f View FIGURE 2 ).

Aedeagus ( Fig. 6 View FIGURE 6 ): Length 0.7 mm; sclerotized ventral process asymmetric, exceeding largely the edge of the dorsal plate ( Figs 6a–c View FIGURE 6 ), with a twisted leaf shape ( Figs 6a, 6c–d View FIGURE 6 ); the base of the ventral process horn-shaped on each side directed inwards and upwards ( Figs 6a, 6c View FIGURE 6 ); dorsal plate cylindrical‒shaped in dorsal view ( Fig. 6b View FIGURE 6 ), with fused lateral lobes ( Fig. 6c View FIGURE 6 ), an inverted V‒shaped sclerotized area towards the ventral process, supporting the upper part and the apical edge of the dorsal plate ( Figs 6b–c View FIGURE 6 ).

Taxonomic, distribution and bionomic remarks

According to Coiffait (1982) taxonomic criteria (e.g. aedeagus with fused lateral lobes and the development of the lateral and ventral process) Domene pedroi sp. nov. should be included also in the subgenus Lathromene . Among other morphological characteristics the species shows a distinctive shape of the aedeagus. Taking into account the pieces of this structure, the new species can be easily segregated from all known Lathromene species with symmetric ventral process ( D. bergidi , D. boavidae sp. nov., D. cantabrica , D. caurelensis , D. darinkae , D. eufemia , D. gridelliana , D. invernadeirensis , D. lusitanica , D. orensis , D. sistelensis , D. suidensis and D. viriatoi ). Among the species with asymmetric ventral process, the closest species to D. pedroi sp. nov. seems to be D. subiasi ( Outerelo, 1977) . However, unlike the new species, the ventral process of D. subiasi presents a dilated axe-shaped apical tip in lateral view (Figs 44, 46 in Outerelo 1977) (leaf-shaped in the new species) and a small tooth directed laterally and obliquely backwards in the middle region on the left side (absent in the new species) (cf. Fig. 6c View FIGURE 6 and fig. 45 in Outerelo 1977). Furthermore, the apical tip is directed outward and in the new species it is directed slightly inward (cf. Fig. 6a View FIGURE 6 and fig. 46 in Outerelo 1977). Regarding morphological characteristics other than those of the aedeagus D. subiasi has a narrow and glabrous median stripe on the upper part of the head and a slight median longitudinal depression without setae in the VII sternite (see figs 40, 42 in Outerelo 1977, respectively), both characteristics are absent in the new species (e.g. see head in Fig. 5a View FIGURE 5 ).

The remaining three species with asymmetric ventral blade are D. scopaeella , D. gallaeciana and D. barraganensis . All can be segregated from the new species by some features of the aedeagus. In the D. scopaeella and D. barraganensis the ventral process has an apical dilated axe-shaped tip that bends inwards at a right angle [see figs 100G–H in Coiffait (1982) and figs 10, 11 in Outerelo & Gamarra (2012), respectively]. Moreover, unlike the new species, the upper part and the apical edge of the dorsal plate in D. barraganensis is not directed towards the ventral process (see fig. 10 in Outerelo & Gamarra 2012). Concerning D. gallaeciana , the ventral process exceeds largely the edge of the aedeagus and from the middle to apex, gradually narrows, becoming filiform towards the tip (see figs 11–14 in Feldmann & Hernando 2005); median region presents also two contiguous lateral expansions that are absent in the new species (ventral view) (fig. 13 in Feldmann & Hernando 2005). Furthermore, in these three species there are no horn-shaped process on each side of the base of the ventral process (present in the new species and in D. subiasi ). Some other morphological characteristics, like the ommatidia number, as well as male sternites VII and VIII features, allow to segregate the new species from D. scopaeella , D. gallaeciana and D. barraganensis too. For instance, D. gallaeciana and D. barraganensis are totally anophtalmous (7 ommatidae in the new species), the latter presents a middle depression on VII sternite and both have black modified setae in the sides of the posteriad excision of sternite VIII (not present in the new species). The congeners with populations closer to the new species are D. lusitanica (from Gruta da Cerâmica, Serra do Sicó, Portugal), D. viriatoi (from Buraco da Moura, Serra da Estrela, Portugal), D. hispanica (from El Cabaco, Salamanca, Spain) and D. subiasi (from Nuñomoral, Cáceres, Spain) (see also fig. 10 in Magrini & Carotti 2019).

Domene pedroi sp. nov. can easily be separated from D. hispanica Outerelo, 1985 also through several characters of the external morphology (e.g. body size, shape and punctuation of the head and pronotum, absence of a median sulcus on the pronotum, femoral tooth of front leg) (see description in Outerelo 1985).

The holotype specimen of D. pedroi sp. nov. was sampled by hand directly among plates of schistose rocks below thin layer of clayey brown-reddish soil on the side slopes of a country road. The locality habitat was dominated by Pinus trees with rock-roses, brooms, lavender and rosemary shrubs [ Cistus ladanifer ( Cistaceae ), Cistus salvifolius ( Cistaceae ), Cytisus spp. ( Fabaceae ), Lavandula sp. ( Lamiaceae ) and Rosmarinus officinalis ( Lamiaceae )].

With no more data on the distribution of the new species than that of the holotype it is provisional accepted that D. pedroi sp. nov. is endemic of Portugal. In the same region and date two endogean ground beetles were also found: Typhlocharis zaballozi Serrano & Aguiar, 2014 and Hypothyphlus lusitanicus Serrano & Aguiar, 2004 (see Serrano & Aguiar 2011, 2014).

According to the assumption of Reboleira et al. (2011b), this small size species would be more connected with the endogean environment. Indeed, D. pedroi sp. nov. was found in a typical endogean environment like D. boavidae sp. nov. (e.g. Fig. 1a View FIGURE 1 ). Taking into account the reduced eyes, lack of hind wings, elongated body shape and long legs it is assumed that it is a subterranean dwelling species.