Mayetia serbica, Hlaváč & Janák, 2024

Hlaváč, Peter & Janák, Jiří, 2024, Endogean and cavernicolous Coleoptera of the Balkans. XXVII. A new species of Mayetia Mulsant et Rey, 1875 (Coleoptera: Staphylinidae: Pselaphinae) from Serbia, Zootaxa 5551 (3), pp. 591-598 : 592-595

Mayetia serbica sp. nov.

Figs 1–19

Material studied: Holotype, ♂: SERBIA, with one label “SERBIA mer. occ. 1.vi.2024 / Mt. Radan , soil washing, 1085m / 43.01894 N, 21.48485 E / J. Janák lgt. beech forest” [white, printed], ( PCPH) . Paratypes, 38♂♂, 33♀♀: same data as for holotype ; 1♀: same data as for holotype but “sifting” ( BMNH, NMPC, PCPH) .

Diagnosis. Eyes completely atrophied; labrum with two pairs of spiny protuberances in both sexes; apex of spiny protuberances variable; left mandible ( Fig. 10 ) with a single tooth, right with bifid tooth; maxillary palpi with palpomere 3 and 4 with large, rounded sensory appendages; antennal club dimerous, scape about 1.5 times as long as wide, antennomeres 3–9 transversal; pronotum inversely trapezoidal; elytra slightly wider than long, lacking foveae, carinae or striae; abdomen with sternite 6 (VIII) in males asymmetric, with deep median excision; legs short and robust, metatrochanter simple, subtriangular, lacking spur; aedeagus elongate, about three times as long as wide.

Description. Body length 1.15–1.20 mm ( Figs 1, 2 ), maximal width in posterior third of visible sternite III and IV, about 0.18-0.19 mm.

Head ( Figs 3–5, 8–10 ) about 1.12–1.17 times as wide as long, about 1.10–1.15 as wide as pronotum, widest in posterior third, from here convergent posteriad and anteriad; basal capsule separated from neck region by occipital constriction, neck region retracted into pronotum, posterior margin of basal capsule deeply concave, posterior lateral corners rounded but strongly protuberant; eyes completely atrophied. Antennal insertions ( Figs 8, 9 ) distant to each other; distance between them slightly inferior of half of head width. Labrum ( Figs 4–7 ) with four spiny protuberances in both sexes; apex of spiny protuberances variable; left mandible ( Fig. 10 ) with a single tooth, right with bifid tooth; maxillary palpi with palpomere 3 and 4 with large, rounded sensory appendages.

Antenna ( Figs 8, 9 ) about 0.22 mm long, antennal club dimerous, scape about 1.5 times as long as wide and about 1.5 times as long as globular pedicel, pedicel as long as wide, antennomeres 3–9 transversal; 3, 4, 6 and 8 subequal in length, 5, 7 and 9 subequal in length, slightly longer than 6; antennomere 5, 7 and 9 strongly transverse, 5 twice as wide as long; 7 2.5 times as wide as long; 9 2.7 times as wide as long; antennomere 10 and 11 subequal in length, 10 bowl-like, 11 conical, with dense setation on anterior half; terminal antennomere with dense setae and flattened sensilla.

Pronotum ( Fig. 11 ) inversely trapezoidal, slightly elongate, about 1.15 times as long as wide, widest slightly anterior to anterior third, from here evenly convergent posteriad; disc slightly convex; anterior and posterior corners round, anterior and posterior margins straight; lacking sulci and foveae.

Elytra ( Fig. 12 ) slightly wider than long, slightly granulate, lacking foveae, carinae or striae; slightly wider and slightly shorter than pronotum

Abdomen elongate, about 1.5 times as long as head, pronotum and elytra combined; first visible tergite (III) shortest, about 1.1 times shorter than 2 (IV) which is about 0.75 of length of 3 (V); tergites 2 (IV) and 4 (VI) subequal in length; sternite 6 (VIII) (Fig. 14) in males asymmetric, with deep median excision, left posterior lobe wide, right one pointed, posterior half with setae; with first visible sternite 1 (III) with confluent metacoxal beds ( Fig. 13 , mtcb); paratergites III–VII well-defined.

Legs ( Fig.13 )short and robust, mesocoxae confluent, oval and long, about 0.4 of combined length of mesoventrite and metaventrite; tibia strongly enlarged in distal half; metatrochanter simple, subtriangular, lacking spur.

Aedeagus (Fig. 15) elongate, about 0.12 mm long, about three times as long as wide.

Sexual dimorphism. Not apparent. FIGURES 14–15. Mayetia serbica sp. nov., holotype: 15a; paratypes: 14a–14b, 15b–15d; 14a–14 b, male visible sternite 6 (VIII); 15a–15b, aedeagus, ventral view; 15c-d, aedeagus, dorsal view. Scales 0.1 mm: 14a–14b; 15a–15d.

Natural history. The majority of specimens were collected by soil-washing (the volume of about 100 litres) from a depth of up to 40 cm under a large stone near a rotting stump close to a stream in a well-preserved beech forest ( Figs 16–19 ). One specimen was collected by sifting of leaves and humus around this stone.

Distribution. Serbia (Radan Mountain)

Remark. Mayetia serbica has the metatrochanter simple, lacking spine. This character state is shared with M. istriensis and M. macedonica while two remaining balkanic species, M. matzenaueri and M. carpatica have the metatrochanter with well-defined spine. M. istriensis and M. macedonica differ from the new species as follows:

• M. istriensis by the different shape of labrum, having spiny protuberances sharply pointed ( Coiffait 1955, Fig. 47); pronotum with median elongate impression; elytra clearly longer than pronotum; and by the different shape of the aedeagus ( Hlaváč & Janák 2024).

• M. macedonica by the different shape of labrum, having three pairs of spiny protuberances in males; shorter scape, about as long as wide; all maxillary palpomeres lacking sensory appendages; and by the different shape of the aedeagus ( Hlaváč & Janák 2024).

Figures

FIGURES 1–9. Mayetia serbica sp. nov., holotype: 1, 4, 8; paratypes: 2–3, 5–7, 9; 1, dorsal habitus of male; 2, dorsal habitus of female; 3, mouthparts of male, ventral view; 4, mouthparts of male holotype, dorsal view; 5, mouthparts of female, dorsal view; 6–7, labrum of males, dorsal view; 8, head and antennae of male, dorsal view; 9, head and antennae of female, dorsal view. Scales 0.5 mm: 1–2; 0.1 mm: 3; 4–7; 8–9.

FIGURES 10–13. Mayetia serbica sp. nov., holotype: 11–12; paratypes: 10, 13; 10, head of male, ventral view; 11, pronotum of male, dorsal view; 12, elytra of male, dorsal view; 13, prosternum, meso- and metaventrite of female; mtcb, metacoxal beds. Scales 0.1 mm: 10; 11–13.

FIGURES 16–17. Radan mountain, type locality of Mayetia serbica sp. nov. Arrows indicate the place where the specimens were found.

FIGURES 18–19. Radan mountain, type locality of Mayetia serbica sp. nov. details of the place where the specimens were found.