Leptomeson soltensis Ćurčić & Rađa, 2019

Ćurčić, Srećko, Vesović, Nikola, Lazović, Vladimir, Pantelić, Dejan & Rađa, Tonći, 2019, A new troglobitic species of the genus Leptomeson Jeannel, 1924 (Coleoptera: Leiodidae: Cholevinae: Leptodirini) from the Island of Šolta (middle Dalmatia, Croatia), Zootaxa 4711 (1), pp. 193-200 : 194-199

Leptomeson soltensis Ćurčić & Rađa , sp. n. ( Figs. 2–16 )

Type material. HT male labelled as follows: “Jama na Idrenici Pit, village of Maslinica, Island of Šolta, MI Dalmatia, Croatia, 23.vii.2016 (hand collecting), TR & AB” (white label, printed) / Holotypus Leptomeson soltensis sp. n. Ćurčić & Rađa det. 2017 (red label, printed) ( NHMS) ( Fig. 2 ). PTs: four females, same data as for HT ( IZFB); five males and nine females labelled as follows: “ Jama na Idrenici Pit , village of Maslinica, Island of Šolta, MI Dalmatia, Croatia, 09.vii.2017 (pitfall trapping), DK, DA & IB” ( IZFB). All PTs are labelled with white, printed locality labels and with red printed labels “ Paratypus Leptomeson soltensis sp. n. Ćurčić & Rađa det. 2017” .

Description. TL R 4.65–5.05 mm, M 4.89 mm, males (M 4.725 mm) smaller than females (M 4.95 mm) (HT 4.65 mm) ( Table 1 ). Integument shiny, of testaceous color, while legs, palps and antennae somewhat lighter. With leptodiroid and elongate body, narrow and elongate pronotum, convex physogastric and scaphoid elytra and wingless ( Figs. 2 and 8 ). Head wider than pronotum, eyeless. Microsculpture weakly expressed, almost absent dorsally ( Figs. 2 , 11 and 14 ), developed ventrally ( Fig. 10 ), nearly isodiametric, pentagonal and hexagonal. Head and pronotum almost glabrous ( Figs. 2 , 9 and 11 ), while elytra with sparsely distributed hairs ( Figs. 15 and 16 ).

Head hypognathous, elongate, with no eyes and occipital carina, widened anteriorly, broader than pronotum, with an impressed vertex ( Figs. 2 and 9 ). Mandibles concave apically, maxillary palps elongate, penultimate palpomere sub-conical, broadened distally, terminal palpomere conical and elongate. Antennae extremely long (BO/AL R 0.58–0.66, M 0.62, in males M 0.58, while in females M 0.64), thin, antennomere 2 shorter than antennomere 1 (A2/A1 R 0.71–0.82, M 0.77), distalmost antennomere longer than preceding (A11/A10 R 1.10–1.31, M 1.17) ( Table 1 ). Both dorsal and ventral surfaces smooth, shiny, with a few sparsely distributed short, erect hairs and small punctures. No microsculpture developed.

Values of AN/AL M R for all specimens, males and females are presented in Table 1 .

Pronotum very narrow and elongate, approximately three times as long as wide (PW/PL R 0.31–0.33, M 0.32, in males M 0.32, while in females M 0.325), constricted in posterior half and very gently prior to 1/3 of its length, widest at anterior margin, at base distinctly narrower, narrowest between 2/3 and 3/4 of its length, AM/BA R 1.15–1.30, M 1.22 ( Figs. 2 , 9 and 11 ; Table 1 ). Lateral margins strongly sinuate basally, slightly concave anteriorly, very finely bordered in basal 2/3 of pronotal length. Hind angles obtuse and blunt, while fore angles obtuse and rounded. Base convex, not bordered. Disc convex both basally (more pronouncedly) and anteriorly, with a concavity between the latter regions. Dorsal surface smooth, shiny, with a few sparsely distributed short hairs and small punctures. No microsculpture developed.

Mesothoracic peduncle elongate, somewhat shorter than pronotal base (MP/BA R 0.80–0.95, M 0.89) ( Table 1 ). Lat- eral margins slightly concave. Scutellum elongate, sub-triangular, with pronounced polygonal microsculpture and slightly concave dorsal surface ( Figs. 12 and 13 ).

Prosternum narrow, elongate, with a long sharp sagittal carina, with pronounced microsculpture. Mesosternum subtriangular, elongate, slightly angled ventrally, with pronounced microsculpture ( Figs. 8 and 10 ), without carina. Mesocoxal cavities widely confluent. Mesosternal process short, sub-triangular. Metasternum huge, slightly wider than long, covered with densely distributed short hairs and punctures, with pronounced microsculpture ( Fig. 10 ). Metacoxal cavities separated. Abdominal ventrites transverse, covered with densely distributed short hairs and punctures, with pronounced microsculpture ( Fig. 10 ).

Elytra elongate, physogastric, scaphoid (EL/EW R 1.82–2.08, M 1.94, in males M 1.98, while in females M 1.93), thick in lateral view ( Fig. 8 ), widest slightly prior to middle, with lateral margins rounded, separated and briefly rounded apically ( Figs. 2 and 14 ) ( Table 1 ). Elytral suture evident. No sutural stria present. Disc strongly convex, smooth, shiny, with sparse and superficial puncturation. No microsculpture developed. Hairs short, sparsely distributed, yellow, erect, slightly denser around elytral median suture and basally, near scutellum ( Figs. 15 and 16 ).

Legs elongate and narrow ( Fig. 2 ). Femora broadened basally, gradually narrowing distally. Tibiae straight and thin both basally and distally. Tarsi not dilated. Protarsomeres pentamerous in males and tetramerous in females. Tarsal claws slightly widened medially, long.

Aedeagus short, robust, almost straight ( Figs. 3 and 5 ). Median lobe in dorsal aspect weakly broadened sub-basally, with a sub-triangular apex, basal bulb short and rounded ( Fig. 3 ). Median lobe in lateral aspect gradually narrowing apically, with a straight pointed apex; basal bulb long and widened ( Fig. 5 ). Parameres elongate, shorter than median lobe, each with three apical setae, in dorsal view curved inwards, gradually narrowing apically, spoon-like and twisted at apex ( Figs. 3 and 4 ), while in lateral view weakly curved, not narrowing apically ( Fig. 5 ). Inner sac with a long chitinized median phanera in the form of a stylet ( Fig. 3 ).

Spermatheca tiny, weakly chitinized, strongly curved, rounded at top ( Fig. 6 ).

Female abdominal sternite VIII large, transverse, with a narrow anterior process, pubescent ( Fig. 7 ).

Differential diagnosis. L. soltensis sp. n. is most closely related to L. dalmatinus and L. bujasi , which inhabit two Croatian Adriatic islands in the surroundings of the Island of Šolta (Čiovo and Brač, respectively) ( Giachino et al., 2011). The three mentioned taxa share the following features: presence of pronotum with weakly expressed microsculpture or without microsculpture, elytral disc with short pubescence, parameres bearing three apical setae each and median lobe of aedeagus of similar shape ( Giachino et al., 2011).

The new species differs from L. dalmatinus in the BO/AL M in males and females (0.58 and 0.64, respectively vs. 0.64 and 0.69, respectively), degree of expression of anterior pronotal constriction (barely distinguished vs. well expressed), PW/PL M in females (0.325 vs. 0.37), MP/BA (mesothoracic peduncle somewhat shorter than pronotal base vs. mesothoracic peduncle about as long as pronotal base), EL/EW M in males and females (1.98 and 1.93, respectively vs. 2.18 and 2.00, respectively), position of maximum width of elytra (slightly prior to middle vs. around at middle), shape of median lobe apex in dorsal aspect (sub-triangular, not protruding vs. not sub-triangular, largely rounded and strongly protruding beak-wise), length of parameres (shorter than median lobe vs. as long as median lobe) and shape of spermatheca (more curved vs. less curved) ( Giachino et al., 2011) ( Table 2 ).

It differs from L. bujasi in the BO/AL M in females (0.64 vs. 0.80), A11/A 10 in females (antennomere 11 longer than antennomere 10 vs. antennomere 11 shorter than antennomere 10), degree of expression of anterior pronotal constriction (barely distinguished vs. well expressed), PW/PL M in males (0.32 vs. 0.28), shape of pronotal base (convex vs. almost straight), MP/BA (mesothoracic peduncle somewhat shorter than pronotal base vs. mesothoracic peduncle about as long as pronotal base), EL/EW M in females (1.93 vs. 1.82), position of maximum width of elytra (slightly prior to middle vs. just beyond middle), shape of median lobe apex in dorsal aspect (not protruding vs. slightly protruding beak-wise), length of parameres (shorter than median lobe vs. as long as median lobe), shape of parameral apex in dorsal aspect (spoon-like, twisted vs. simple, narrow) and shape of spermatheca (less widened distally vs. more widened distally) ( Giachino et al., 2011) ( Table 2 ).

Etymology. The species is named after the Island of Šolta, MI Dalmatia, Croatia, on which is situated the type locality.

Type locality. Jama na Idrenici Pit , village of Maslinica, Island of Šolta, MI Dalmatia, Croatia .

Distribution. The new species currently inhabits solely the Jama na Idrenici Pit.

Habitat. The type specimens were collected by hand and pitfall trapping with rotten meat as bait in the deepest, totally dark part of the Jama na Idrenici Pit, on vertical limestone walls with a high level of humidity (presence of trickling water).

Figures

FIGURES 2–7. Leptomeson soltensis sp. n. from the Jama na Idrenici Pit, village of Maslinica, Island of Šolta, MI Dalmatia, Croatia. 2—holotype male, habitus (dorsal view); 3—holotype male, aedeagus (dorsal view); 4—holotype male, left paramere apex (dorsal view); 5—holotype male, aedeagus (lateral view); 6—paratype female, spermatheca (lateral view); 7—paratype female, abdominal segment VIII. Scales = 1 mm (Fig. 2), 100 μm (Figs. 3, 5 and 7) and 50 μm (Figs. 4 and 6).

FIGURES 8–10. Leptomeson soltensis sp. n. from the Jama na Idrenici Pit, village of Maslinica, Island of Šolta, MI Dalmatia, Croatia. 8—paratype female, habitus (lateral view); 9—paratype female, head and pronotum (lateral view); 10—paratype female, mesosternum, metasternum and abdomen (ventral view). Scales = 1.0 mm (Fig. 8) and 0.5 mm (Figs. 9 and 10).

FIGURES 11–16. Leptomeson soltensis sp. n. from the Jama na Idrenici Pit, village of Maslinica, Island of Šolta, MI Dalmatia, Croatia. 11—paratype female, pronotum (dorsal view); 12—paratype female, mesothoracic peduncle (dorsal view); 13—paratype fe- male, microsculpture of scutellum (dorsal view); 14—paratype female, elytra (dorsal view); 15—paratype female, basal part of elytra (dorsal view); 16—paratype female, elytral hairs (dorsal view). Scales = 250 μm (Fig. 14), 200 μm (Fig. 11), 100 μm (Figs. 12 and 15), 50 μm (Fig. 16) and 20 μm (Fig. 13).

Tables

TABLE 1. Linear measurements and morphometric ratios in Leptomeson soltensis sp. n. Numerical values out of parentheses represent mean values, while those in parentheses are ranges (* - values in mm).

	All specimens	Males	Females
No. of examined specimens	12	4	8
TL*	4.89 (4.65–5.05)	4.725 (4.65–4.80)	4.95 (4.70–5.05)
BO/AL	0.62 (0.58–0.66)	0.58 (0.58–0.59)	0.64 (0.62–0.66)
A2/A1	0.77 (0.71–0.82)	0.79 (0.76–0.82)	0.76 (0.71–0.815)
A11/A10	1.17 (1.10–1.31)	1.26 (1.21–1.31)	1.14 (1.10–1.17)
A1/AL	5.46 (5.23–5.78)	5.505 (5.23–5.78)	5.43 (5.27–5.53)
A2/AL	4.27 (4.065–4.38)	4.34 (4.30–4.38)	4.22 (4.065–4.30)
A3/AL	10.21 (9.77–10.98)	10.03 (9.96–10.09)	10.33 (9.77–10.98)
A4/AL	10.01 (9.53–10.57)	9.85 (9.53–10.16)	10.12 (9.84–10.57)
A5/AL	12.50 (12.15–13.09)	12.15 (12.15)	12.73 (12.50–13.09)
A6/AL	10.285 (10.09–10.57)	10.13 (10.09–10.16)	10.39 (10.25–10.57)
A7/AL	10.52 (10.28–10.74)	10.42 (10.28–10.56)	10.59 (10.45–10.74)
A8/AL	9.05 (8.37–9.375)	8.76 (8.37–9.16)	9.25 (9.15–9.375)
A9/AL	9.28 (8.54–9.72)	9.44 (9.16–9.72)	9.18 (8.54–9.57)
A10/AL	10.035 (9.35–10.96)	10.80 (10.65–10.96)	9.52 (9.35–9.84)
A11/AL	8.38 (8.13–8.785)	8.58 (8.37–8.785)	8.245 (8.13–8.40)
PW/PL	0.32 (0.31–0.33)	0.32 (0.32–0.325)	0.325 (0.31–0.33)
AM/BA	1.22 (1.15–1.30)	1.23 (1.20–1.26)	1.22 (1.15–1.30)
MP/BA	0.89 (0.80–0.95)	0.87 (0.84–0.90)	0.90 (0.80–0.95)
EL/EW	1.94 (1.82–2.08)	1.98 (1.87–2.08)	1.93 (1.82–2.05)

TABLE 2. Main morphological differences between Leptomeson soltensis sp. n. and the most related species L. dalmatinus and L. bujasi. Source of data: Giachino et al. (2011), current paper.

Character	Leptomeson soltensis sp. n.	L. dalmatinus	L. bujasi
BO/AL M in males and females	0.58 and 0.64, respectively	0.64 and 0.69, respectively	0.55 and 0.80, respectively
A11/A10 in females	Antennomere 11 longer than antennomere 10	Antennomere 11 longer than antennomere 10	Antennomere 11 shorter than antennomere 10
Degree of expression of anterior pronotal constriction	Barely distinguished	Well expressed	Well expressed
PW/PL M in males and females	0.32 and 0.325, respectively	0.30 and 0.37, respectively	0.28 and 0.30, respectively
Shape of pronotal base	Convex	Convex	Almost straight
MP/BA	Mesothoracic peduncle somewhat shorter than pronotal base	Mesothoracic peduncle about as long as pronotal base	Mesothoracic peduncle about as long as pronotal base
EL/EW M in males and females	1.98 and 1.93, respectively	2.18 and 2.00, respectively	2.00 and 1.82, respectively
Position of maximum width of elytra	Slightly prior to middle	Around at middle	Just beyond middle
Shape of median lobe apex in dorsal aspect	Sub-triangular, not protruding	Not sub-triangular, largely rounded and strongly protruding beak-wise	Slightly protruding beak-wise
Length of parameres	Shorter than median lobe	As long as median lobe	As long as median lobe
Shape of parameral apex in dorsal aspect	Spoon-like, twisted	Spoon-like, twisted	Simple, narrow
Shape of spermatheca	More curved, less widened distally	Less curved	More widened distally