Derossiella lukici, Lohaj & Delić, 2019

Lohaj, Roman & Delic, Teo, 2019, Playing hard to get: two new species of subterranean Trechini beetles (Coleoptera, Carabidae, Trechinae) from the Dinaric Karst, Deutsche Entomologische Zeitschrift 66 (1), pp. 1-15 : 1

Derossiella lukici sp. n. Figs 2 , 3 , 4 , 5

Type series.

Holotype male labelled: "Croatia, Mt Biokovo, Golubinjak, Biokovka, -300 m, 24.6.2017, T. Delić lgt." (white label, printed) / "DNA extraction RL-07" (orange label, printed) / "HOLOTYPUS Derossiella lukici sp. n. Lohaj & Delić des. 2018" (red label, printed), (CNHM, voucher code 600: ZAG; ZEC2, 4194 Coll. Jalžić). Paratypes: one female (right posterior tarsus missing) labelled: "Croatia, Mt Biokovo, Golubinjak, Biokovka, 2.9.2007, M. Lukić lgt." (white label, printed) / "PARATYPUS Derossiella lukici sp. n. Lohaj & Delić des. 2018" (red label, printed), (CNHM, voucher code 600: ZAG; ZEC2, 4195 Coll. Jalžić)., one female (last three antennomeres of right antenna missing) labelled: "Croatia, Mt Biokovo, Lokva, Pretnerova, -120 m, 19.05.2015, E. Premate lgt." (white label, printed) / "PARATYPUS Derossiella lukici sp. n. Lohaj & Delić des. 2018" (red label, printed), (CRL).

Diagnosis.

Medium-sized aphaenopsoid trechine with morphological features fully matching generic description proposed by Quéinnec (2008). Head long, parallel-sided, with complete, deep frontal furrows reaching neck constriction and two pairs of supraorbital setae, posterior setae doubled. Eyes absent, mentum with simple tooth. Aphaenopsoid habitus with very narrow head and pronotum; elytra oblong-oval, 2.6 times wider than head and pronotum. Hind angles of pronotum without setae. Surface completely glabrous, striae absent, elytral chaetotaxy with macrochetae and microchetae. Cuticle depigmented, reddish-yellow, body strongly flattened dorso-ventrally, with very long and slender legs and antennae (Figs 3 , 4 ). Closely related to the type species of the genus, Derossiella nonveilleri , from which it differs by paired posterior supraorbital setiferous punctures, differently shaped elytra with higher number of macro- and microchetae, narrower pronotum, as well as by the differently shaped aedeagus.

Description.

L: 5.5 mm (PT)-6.0 mm (HT), TL: 4.8 mm (PT)-5.4 mm (HT). Head relatively large, nearly parallel-sided, with maximum width behind middle, distinctly longer than wide (index HL/HW 1.35 (PT)-1.42 (HT), slightly wider than pronotum, sparsely pubescent. Frontal furrows deep, complete, reaching neck constriction, slightly divergent posteriorly. Anterior pair of supraorbital setae situated before middle of head length, posterior supraorbital setae paired, two setae on each side of head situated close to neck constriction. Neck constriction distinct; genae gently convex. Clypeus and labrum with three pairs of setae, outer pairs longer. Antennae length 4.9 mm (HT)-4.3 mm (PT), scape as long as pedicel, almost as long as terminal antennomere.

Pronotum elongated, slightly longer and narrower than head, with maximum width in anterior third, index PL/PW 1.75 (PT)-1.83 (HT), only slightly narrowed anteriorly, posterior part distinctly narrower than anterior. Surface glabrous, median furrow distinct, visible in whole pronotal length. Propleura visible from dorsal aspect in basal two-thirds. Anterior angles of pronotum not protruding, posterior angles obtuse. Lateral furrows well developed, deep, with one pair of anterolateral setae, situated in the apical fifth of pronotal length.

Elytra subovate elongate, distinctly longer than wide, index EL/EW 1.74 (PT)-1.85 (HT), with maximum width in posterior third; elytral surface glabrous, without pubescence; striae absent. Stria 3 with 4-5 (3-4 discal and one preapical) macrochetae and 3 or 4 microchetae situated between macrochetae, stria 5 with 4 or 5 microchetae (Fig. 4 ). Humeral group of umbilicate pores not aggregated, first anterior pore of humeral group isolated and situated at level of the first discal seta.

Legs long, slender, densely pubescent. First two tarsomeres of male protarsi distinctly dilated and protracted at their internal margins. Tarsal claws very long and slender, without traces of denticulation on their internal sides.

Male genitalia. Aedeagus (Fig. 5 ) 0.58 mm long, relatively robust, regularly wide, lacking apical constriction, laterally flattened. Parameres relatively long and slender, longer than half of the length of aedeagus. Apex very short, tip obtuse. Each paramere at apex with three setae, two long, and one short.

Female genitalia as in Figure 5 .

Etymology.

Patronymic, dedicated to our dear friend Marko Lukić (Zagreb, Croatia), enthusiastic speleologist and speleobiologist, taxonomic specialist on subterranean Collembola, and collector of the first specimen of the new species.

Differential diagnosis.

Derossiella lukici sp. n. is closely related to the type species of the genus, Derossiella nonveilleri . However, these two species can be easily recognized using the following key:

1(2)	Head with 2 posterior supraorbital setiferous punctures on each side, which are very close to each other. Elytra with maximum width in the posterior third. Putative stria 3 with 4 or 5 macrochetae and 4-6 microchetae, putative stria 5 with 3 or 4 microchetae (Fig. 4 ). Pronotum narrower, index PL/PW: 1.75-1.83, anterior angles not protruding. Aedeagus (Fig. 5 ) shorter, more robust. L: 5.5-6.0 mm. Croatia, Mt Biokovo	Derossiella lukici sp. n.
2(1)	Head with only 2 posterior supraorbital setiferous puncture on each side. Elytra with maximum width in middle. Putative stria 3 with 3 macrochetae and 2 microchetae between each macrochetae, putative stria 5 with 1 microcheta in basal fourth (see Fig. 4 ). Pronotum wider, index PL/PW: 1.43-1.44, anterior angles slightly protruding. Aedeagus (Fig. 5 ) longer and slenderer. L: 5.4-5.8 mm. Croatia, Mt Mosor	Derossiella nonveilleri Quéinnec, 2008

Distribution.

So far this species is known from the two pits on Mt Biokovo, the type locality, Biokovka, Golubinjak and Pretnerova jama, Lokva. All three specimens were found in deeper parts of the caves, attaining depths of 120 to 300 m. They were all found walking on the “moonmilk”, a white, pastelite material consisting of microbiologically transformed microcrystalline calcites with high water content (60-90%), and near the cave hygropetric.

Associated subterranean coleopteran fauna observed in the pits:

1 Biokovka, Golubinjak, Biokovo, Croatia:

Carabidae : Trechinae

Neotrechus dalmatinus (Miller, 1861)

Leiodidae : Cholevinae

Leptomeson biokovensis Giachino, Bregović & Jalžić, 2012

Radziella styx Casale & Jalžić, 1988

Speoplanes giganteus biocovensis Müller, 1934

2 Pretnerova jama, Lokva, Biokovo, Croatia:

Carabidae : Trechinae

Dalmataphaenops chiarae Monguzzi, 1993

Carabidae : Sphodrini

Laemostenus cavicola (Schaum, 1858)

Leiodidae : Cholevinae

Leptomeson biokovensis Giachino, Bregović & Jalžić, 2012

Radziella styx Casale & Jalžić, 1988

Speoplanes giganteus biocovensis Müller, 1934

Staphylinidae : Pselaphinae

Pselaphinae gen.

Figures

Figure 2. Geographical distribution of the Dinaric aphaenopsoid trechines of the genera Derossiella and Adriaphenops. Source of data: http: // subbio. net / db /

Figure 3. Derossiella lukici sp. n. in its habitat in the cave Biokovka, Golubinjak, Mt Biokovo (Photo courtesy of P. Bregovic).

Figure 4. Habitus of Derosiella species. Derossiella lukici sp. n. (a) and Derossiella nonveilleri (b). Chetotaxy is presented as white points (photo courtesy of Dusan Beno).

Figure 5. Male and female genitalia of Derossiella representatives: aedeagus of D. lukici sp. n., dorsal view (a); and lateral view (b); female genitalia gonocoxite 1 and 2 (basal and apical segments of gonostylus) copulatory piece of D. lukici sp. n. (c); and D. nonveilleri, lateral view of male aedeagus with parameres detached (d) (illustration by Fedor Ciampor).