Eupolybothrus liburnicus, Akkari, Nesrine, Komericki, Ana, Weigand, Alexander M., Edgecombe, Gregory D. & Stoev, Pavel, 2017

Akkari, Nesrine, Komericki, Ana, Weigand, Alexander M., Edgecombe, Gregory D. & Stoev, Pavel, 2017, A new cave centipede from Croatia, Eupolybothrusliburnicus sp. n., with notes on the subgenus Schizopolybothrus Verhoeff, 1934 (Chilopoda, Lithobiomorpha, Lithobiidae), ZooKeys 687, pp. 11-43 : 11-12

Eupolybothrus liburnicus sp. n. Figs 1, 2, 3, 4, 5, 6, 11H, 12A, C

Material.

Holotype. Ad. ♂, Croatia, Obrovac, Gornji Čabrići, cave Plitka peć, under rock, 09.II.2013, A. Komerički leg., CBSS - CHP 545.

Paratypes. Croatia, Southern Velebit: 2 ♀, Obrovac, Gornji Čabrići, cave Plitka peć, 23.VI.2012, T. Vujnović, A. Komerički & R. Baković leg., CBSS - CHP 538; 6 juv., Obrovac, Gornji Čabrići, cave Plitka peć, 23.VI.2012, A. Komerički leg., CBSS - CHP 541; 2 ♂♂ subadult, Obrovac, Gornji Čabrići, cave Plitka peć, 20.III.2013, K. Miculinić & A. Komerički leg., CBSS - CHP543); 1 ♀, Obrovac, Gornji Čabrići, cave Plitka peć, 23.V.2013, P. Rade & T. Čuković leg., NHMW8409; 1♂, 1 ♀, Obrovac, Gornji Čabrići, cave Plitka peć, 23.V.2012, P. Rade leg., NMNHS CHILOPODA -2016-0003; 1 ♀, Seline, cave Markova špilja, under rock, 01.V.2010, J. Bedek leg., CBSS - CHP 407, BOLD ID: EUCR 048; 1 ♀, Obrovac, Krnjeza canyon, cave Bundalova pećina, 11.VII.2009, R. Baković leg., CBSS - CHP 448; BOLD ID: EUCR 052; 1 ♀, Obrovac, Gornji Čabrići, cave Plitka péc, 29.IX.2009, M. Hodžić leg., CBSS - CHP 457, BOLD ID: EUCR 067; 1 ♂, subadult, Obrovac, Gornji Čabrići, cave Skorupuša, 29.IX.2010, A. Ćukušić leg., CBSS - CHP 458, BOLD ID: EUCR068; 2 ♀♀, 1 juv. Obrovac, Gornji Čabrići, cave Skorupuša, 23.VI.2012, A. Komerički leg., CBSS - CHP539; 7 juv. Obrovac, Gornji Čabrići, cave Skorupuša, 23.VI.2012, A. Komerički leg., CBSS - CHP 540; 1 ♂, 1 juv. Obrovac, Gornji Čabrići, cave Rašeljkovac, 23.VI.2012, A. Komerički leg., CBSS - CHP 544; 1 ♀, Obrovac, Gornji Čabrići, cave Rašeljkovac, 20.III.2013, A. Komerički leg., ZMUC 00040236; 1 ♂, Obrovac, Gornji Čabrići, cave Rašeljkovac, 23.IV.2013, K. Miculinić leg., ZMUC 00040237; Mid-body segments and detached legs, Obrovac, Gornji Čabrići, cave Rašeljkovac, 23.V.2013, K. Miculinić leg., CHP: 551, NMNHS CHILOPODA -2016-0001; head and anterior segments, Obrovac, Gornji Čabrići, cave Rašeljkovac, 20.III.2013, A. Komerički leg., CHP: 547, NMNHS CHILOPODA -2016-0002.

Diagnosis.

A species morphologically similar to E. cavernicolus , genetically differing from it by 11% interspecific distance based on COI, and morphologically differing by the slightly convex posterior margin of T14, presence of 15CxVp and 15PDp spines, and by the leg 15 to body length ratio of ca. 64% in the adult male.

Description.

Males. Based on holotype CHP545 (light photographs) and paratype ZMUC 00040237 (SEM).

Body length: (from anterior margin of cephalic plate to posterior margin of telson) approx. 30 mm.

Colour: tawny-brown to yellowish, ventral part and legs paler (Fig. 1A).

Head: cephalic plate slightly broader than long (3.6 × 3.1 mm, respectively) and wider than T1 (Fig. 1B); surface smooth, with numerous scattered setae. Cephalic median sulcus contributing to biconvex anterior margin, marginal ridge with a median thickening; posterior margin straight to slightly concave; transverse suture situated at about 1/3rd of anterior edge; posterior limbs of transverse suture visible, connecting basal antennal article with anterior part of the ocellar area.

Ocelli: 1+14 blackish irregular ocelli in 3-4 rows; outermost first seriate ocellus largest; ocelli of the middle two rows medium-sized, those of inferior row smallest (Fig. 1C).

Tömösváry’s organ: moderately large (as large as a medium ocellus), oval and situated on a sub-triangular sclerotisation below the inferiormost row of seriate ocelli.

Clypeus: showing a cluster of 25 setae situated on the apex and near the lateral margins (Fig. 2A).

Antennae: ca. 19.8 mm long, ultimate and penultimate articles of same length (Fig. 2B); left antenna composed of 61 articles, right antenna 57 articles; slightly surpassing posterior margin of T7 (right) or T9 (left) when folded backwards, basal two articles enlarged and less setose; the posterior 30 articles visibly longer than broad. Antenna to body length ca. 66%.

Forcipular segment (Figs 2C, 3A): coxosternite subpentagonal (Fig. 2C), shoulders almost absent (steep), lateral margins straight; anterior margin set off as a rim by furrow; coxosternal teeth 8+7, median diastema small, V-shaped, steep and narrow, short porodont arising from a pit below the dental rim, situated lateral to the lateralmost tooth; base of porodont as thin as adjacent tooth (Fig. 3A, po); coxosternite sparsely setose anteriorly; setae moderately large, irregularly dispersed (Fig. 3A). Forcipular trochanteroprefemur, femur and tibia and proximal part of forcipular tarsungulum with several setae. Distal part of forcipular tarsungulum about 3 times longer than proximal part, ca. 2 mm long (Fig. 2C).

Tergites: T1 wider than long, subtrapeziform, wider anteriorly, posterior margin straight or slightly emarginated, marginal ridge with a small median thickening; TT3 and 5 more elongated than T1, posterior margin slightly emarginated medially, posterior angles rounded; posterior angles of T4 rounded; posterior margin of T8 slightly emarginated medially, angles rounded; TT6 and 7 with posterior angles abruptly rounded (Fig. 3B); TT9, 11, 13 with well-developed posterior triangular projections (Fig. 3B, C); posterior margin of TT10 and 12 distinctly emarginated, that of T14 slightly convex, all strongly setose on posterior margin; intermediate tergite hexagonal, with a membranous area reaching up the 2/3rd of its length (Fig. 11H) and posterior margin straight, lateral edges thickened and covered with setae (Fig. 4A); middle part of posterior third of tergite densely covered with setae (Fig. 5F); laterally, on both sides of the central setose area are two bare subtrapezoidal spots (Fig. 4A). All tergites smooth, setae present only along their lateral margins.

Legs: leg 15 ca. 64% body length; leg 14 approx. 25% longer than legs 1-12, leg 13 only slightly longer than legs 1-12; pretarsus of legs 1-14 with stouter posterior accessory claw (approx. as long as fundus) and a slightly thinner anterior accessory claw (= spine, sensu Bonato et al. 2010) (Figs 4B, C); pectinal (seriate) setae missing on tarsus1 and 2 of leg 15, present in one short row on tarsus 2 of leg 14, in one row on tarsus 1 and two rows on tarsus 2 of legs 1-13, (Fig. 3D, ss); pretarsus of leg 15 without accessory spines (Fig. 4C). Length of podomeres of leg 15: coxa 1 mm, prefemur 2.7 mm, femur 3.0 mm, tibia 5.3 mm, tarsus 1 4.8 mm, tarsus 2 2.3 mm, pretarsus 0.2 mm. Prefemur of leg 15 with a large proximal knob (Fig. 5A, pk) protruding mediad and bearing a cluster of long setae dorsally (Figs 5B, 11H), in dorsal view the knob as broad as the prefemur, mesally continuing in a ridge reaching 2/3rd of the prefemur length and gently narrowing distad (Fig. 5A, pr). Posterior edge of prefemur with a well-defined circular protuberance densely covered with short, thin setae, situated between p and m spines dorso-medially (Fig. 5A, cp); rest of prefemur covered with sparse setae. Dorsal spine p on prefemur with furcate tip, also noticed on other podomeres and legs (Fig. 5C). Legs 1-14 without particular modifications.

Coxal pores: generally round, arranged in 6-7 irregular rows, pores of inner rows largest, size decreasing outwards; pores separated from each other by a distance more than or equal to their diameter; number of pores on leg-pair (measured on right leg) 12: 51, 13: 61, 14: 15: 44 (Fig. 5D).

Sternites: smooth, subtrapeziform, with few sparse setae, mainly at lateral margins; posterior margins straight.

Genitalia: posterior margin of male first genital sternite concave, posterior margin densely covered with long setae, the rest of sternite sparsely covered with shorter ones (Fig. 5E); gonopod small, concealed above sternite.

Plectrotaxy: as in Table 1.

Description of the female, based on paratype NHMW 8409 (Fig. 6A, B).

Body length: ca. 43 mm; leg 15 ca. 22.8 mm or 52.9% body length.

Colour: uniformly tawny-brown to yellowish.

Head: cephalic plate broader than long (4 × 3.7 mm, respectively).

Ocelli: 18 blackish subequal ocelli in 6-7 rows.

Tömösváry’s organ: moderately large (as large as or slightly larger than a medium ocellus), oval, situated slightly above the cephalic edge below the inferiormost row of ocelli.

Clypeus: with a cluster of ca. 25 trichoid setae situated on the apex and lateral margins.

Antennae: approx. 18.5 mm long, composed of 73 articles.

Forcipular segment: coxosternite subpentagonal, shoulders almost absent, lateral margins straight; anterior margin set off as a rim by furrow; coxosternal teeth 9+8.

Tergites: T1 wider than long, subtrapeziform, wider anteriorly, posterior margin straight or slightly emarginated, marginal ridge with a small median thickening; TT3 and 5 more elongated than T1, posterior margin slightly emarginated medially, posterior angles rounded; posterior angles of T4 rounded; posterior margin of T8 slightly emarginated medially, angles rounded; TT6 and 7 with posterior angles abruptly rounded; TT9, 11, 13 with well-developed posterior triangular projections; posterior margin of TT10 and 12 slightly emarginated, that of T14 transverse, all with scarce setae on posterior margin; intermediate tergite hexagonal, posterior margin slightly concave, lateral edges setose, its surface with scattered setae in a few rows located on the lateral margins and the posterior half (Fig. 6A). The rest of the tergites smooth, setae present only on lateral margins.

Legs: leg 15 longest ca. 22.8 mm, 53% of body length; leg 14 ca. 17 mm, leg 13 ca. 10.6 mm only slightly longer than legs 1-12, midbody leg (ca. 10 mm); pretarsus of legs 1-14 with a more expanded fundus, larger posterior accessory claw (approx. 1/3rd of fundus) and a slightly thinner and shorter anterior accessory claw; pectinal (seriate) setae lacking on tarsi 1 and 2 of leg 15, present in one short row on tarsus 2 of leg 14, and in one row on tarsus 1 and two rows on tarsus 2 of legs 1-13; pretarsus of leg 15 without accessory spines. Leg 15 slender and elongate, without particular modifications.

Coxal pores: generally round, forming 6-7 irregular rows, pores of inner rows largest, size decreasing outwards; pores separated from each other by a distance more than or equal to their own diameter (Fig. 6B).

Sternites: smooth, subtrapeziform, with few sparse setae, mainly at lateral margins; posterior margins straight.

Female gonopods: densely setose, with 2+2 long, slim and pointed spurs slightly bent and a single blunt claw; outer spur 1.5 longer than the inner one, approx. 5 times longer than broad at base (Fig. 6B).

Etymology.

Liburnicus denotes "of Liburnia", a district in the coastal region of the northeastern Adriatic; adjective.

Variation.

The proximal knob on the male prefemur is substantially smaller in immature males than in mature specimens. For example, CHP544 (body length 11.6 mm) has the prefemoral knob represented by only a low swelling that lacks setae (Fig. 6C), and the medial ridge extending from that swelling is low but distinct; the posterior circular, setose protuberance of adults is indistinct at this size. The posterior part of T14 bears relatively sparse setae, but the tergite of the intermediate segment has a field of dense setae on each side of the midline, and leg 15 is 61% of body length (versus 64% in the holotype). In a male of body length 8.8 mm (CHP543), the prefemur has only a faint bulge in the position of the proximal knob (Fig. 6D), but the tergite of the intermediate segment has a fringe of dense setae on each side of the desclerotized median strip. The female gonopods display spurs with a consistent number (2+2) and sharp, slender shape, with the outer spur on the order of 1.5 times the length of the inner spur. Forcipular teeth are most numerous in the largest specimens, with 6+6 or 7+7 teeth the usual number in specimens less than 25 mm long; some small specimens (e.g., CHP457, body length 10.4 mm) have only 5+5 teeth.

Habitat.

E. liburnicus sp. n. is here recorded from five caves of the Velebit Mountain, Croatia. Four of these (Plitka peć, Skorupuša, Rašljekovac and Bundalova pećina) are situated in the area where the southern slopes of the Crnopac Massif meet the Krupa River canyon while one of them, Markova špilja, is a small anchialine cave situated a few hundred meters from the Adriatic coast near the village of Seline.

The type locality is Plitka peć (Fig. 7), a cave near the village Gornji Čabrići, Obrovac, Zadar County, Croatia. It was formed in Paleogene and Neogene limestone breccias. The cave is small, approx. 30 m long, with a large entrance and a thick layer of sediment on the floor, rich in flowstone and speleothems. The climatic conditions in Plitka peć as measured on 29 September 2010 are as follows: air temperature=12.7° C, sediment temperature=11.4° C, relative humidity=100%. The specimens were collected in both photic and aphotic zones, under stones and in the sediment. The cave is inhabited by spiders of the family Linyphiidae ; Pseudoscorpiones : Neobisium elegans Beier, 1939, Chthonius (Globbochthonius) sp.; Isopoda : Alpioniscus sp., Androniscus sp., Cyphopleon sp., Collembola : Neelidae , Tullbergiidae , Lepidocyrtus sp. ( Bregović et al. 2013).