Enghoffosoma zebra, Likhitrakarn, Natdanai, Golovatch, Sergei I. & Panha, Somsak, 2014

Likhitrakarn, Natdanai, Golovatch, Sergei I. & Panha, Somsak, 2014, Review of the Southeast Asian millipede genus Enghoffosoma Golovatch, 1993 (Diplopoda, Polydesmida, Paradoxosomatidae), with descriptions of new species, Zootaxa 3811 (4), pp. 491-514 : 493-497

Enghoffosoma zebra sp. n.

Figs 1–7

Holotype male ( CUMZ), Thailand, Nakhon Ratchasima Province, Wang Nam Khiao District, Sakaerat Environmental Research Station, ca 450 m a.s.l., 14°30'24"N, 101°55'41"E, 0 3.10.2013, leg. C. Sutcharit and W. Siriwut.

Paratypes. 3 males, 5 females ( CUMZ), 1 male, 1 female ( ZMUC), same data, together with holotype. 3 males, 2 females ( CUMZ), 2 males, 1 female ( ZMUM), 2 males, 1 female ( NHMW), same locality, 24.04.2009, leg. S. Panha, C. Sutcharit and N. Likhitrakarn. 3 males, 1 female ( CUMZ), Ubon Ratchathani Province, Khong Chiam District, Tadtone, ca 175 m a.s.l., 15°15'14"N, 105°00'53"E, 14.05.2011, leg. S. Panha, C. Sutcharit and N. Likhitrakarn. 1 male, 2 females ( CUMZ), same Province, Nam Yuen District, Numtip Temple, ca 220 m a.s.l., 14°27'08"N, 105°00'53"E, 10.10.2010, leg. S. Panha, C. Sutcharit and N. Likhitrakarn. 2 males, 1 female ( CUMZ), same District, Yod Dom Forest Reserve, 160 m a.s.l., 14°26'04"N, 105°06'13"E, 10.10.2010, leg. C. Sutcharit and N. Likhitrakarn. 2 males ( CUMZ), Laos, Champasak Province, Pathoumphone District, Ban Xanapho, ca 110 m a.s.l., 14°44'12"N, 105°57'47"E, 22.07.2013, leg. C. Sutcharit.

Name. To emphasize a stripy, zebra-like colour pattern; noun in apposition.

Diagnosis. Differs from congeners in the characteristic colour pattern of blackish to blackish brown bands with contrasting dark brown to whitish posterior halves of meta- and paraterga, coupled with the gonopod showing a prominent process e and an even stronger, twisted solenomere (sl) (see also Key below).

Description. Length 26–38.5 mm (male) or 26.5–40 mm (female), width of midbody pro- and metazonae 2.9–4.5 and 3.5–5.2 mm (male) or 3.5–5.0 and 4.1–5.4 mm (female), respectively.

Coloration of live animals blackish to blackish brown with a pattern of contrasting dark brown to whitish posterior halves of collum, metaterga, paraterga and epiproct, of dark brown to light brown ( Fig. 1 A–C) or carmine to light pink legs and antennae ( Fig. 1 D); coloration in alcohol, after a long time of preservation, blackish brown to light brown, posterior halves of collum, metaterga, paraterga and epiproct mostly light brown to whitish ( Figs 2 A–F & J–L), antennae and legs dark brown to light brown ( Figs 2 A–F, J & K) or carmine to light pink ( Fig. 2 L), venter and a few basal podomeres light yellow to whitish ( Figs 2 A–F, J & K) or light crimson to light pink, legs growing crimson distally ( Fig. 2 L).

Clypeolabral region sparsely setose, vertex bare, epicranial suture distinct. Antennae rather short ( Figs 1 A–D, 2A & L), clavate (antennomere 6 highest), extending behind body segment 3 (male) or 2 (female) when stretched dorsally. In width, head <segment 3 = 4 <collum <segment 5 <2 <6–17 (both sexes), gently and gradually tapering thereafter. Collum with three transverse rows of setae: 4+ 4 in anterior, 3+ 3 in intermediate, and 5+ 5 in posterior row; caudal corner of paraterga very broadly rounded, declined, not extending behind rear margin ( Figs 2 A, B & L).

Tegument smooth and shining, prozonae finely shagreened, metaterga smooth and leathery, posterior halves delicately rugulose; surface below paraterga finely microgranulate ( Figs 2 A–F & J–L). Postcollum metaterga with two transverse rows of setae traceable at least as insertion points when setae broken off: 3(4)+3(4) in anterior (presulcus), 4+ 4 in posterior (post-sulcus) row, caudal row barely traceable as insertion points. Tergal setae long and slender, about 1/3 of metatergal length. Axial line invisible. Paraterga rather well developed ( Figs 2 A–F & J–L), mostly slightly upturned, all lying below dorsum, set at about half of body height, subhorizontal, caudal corner almost or fully pointed, produced beyond rear tergal margin until segment 15, increasingly rounded and smaller on following segments; posterior edge nearly straight ( Figs 2 A–F & J–L). Calluses on paraterga narrow, delimited by a sulcus only dorsally. Paraterga 2 broad, anterior edge angular to rounded, lateral edge without incision ( Figs 2 A, B & L). Ozopore evident, lateral, lying in an ovoid groove at about 1/4 of metatergite’s length in front of caudal corner. Transverse sulcus at most faint and abbreviated ( Figs 2 A–F & J–L). Stricture between pro- and metazonae narrow, deep, line-shaped, clearly beaded at bottom down to base of paraterga ( Figs 2 A–E & J). Pleurosternal carinae strongly developed, complete crests with a very sharp caudal tooth in segments 2–17, a very small caudal tooth in segment 18, absent from segment 19 (both sexes) ( Figs 2 B, D & E). Epiproct ( Figs 2 E–G) conical, flattened dorsoventrally, with two small apical papillae; tip subtruncate; pre-apical papillae very small, but visible, lying rather close to tip. Hypoproct roundly subtriangular, setiferous knobs at caudal edge very small and wellseparated ( Fig. 2 G).

Sterna very densely setose, with a small cone caudally near each coxa, rear cones being a little larger than front ones ( Fig. 3 D); a rather large, linguiform, densely setose, sternal lobe between male coxae 4 ( Figs 2 H & I). Legs moderately long and slender, midbody ones ca 1.0–1.2 (male) or 1.1–1.3 times (female) as long as body height, prefemora with a lateral bulge growing gradually reduced towards telson ( Fig. 3 E), these bulges being especially strong in male; ventral brushes on male tibiae and tarsi traceable until legs of segment 16 ( Fig. 3 E).

Gonopods ( Figs 3 A–C & 4–7) with subcylindrical and long coxae, sparsely setose distoventrally. Femorite about 3 times as long as prefemoral (= strongly setose) part. Femorite rather stout and long, slightly curved and enlarged distad, parabasal subventral process p pointed, rather short or long ( Figs 3 A–C, 5, 6C & D), up to broadly lobe-shaped ( Figs 4 C, D & 7) or unciform ( Figs 4 A, B & 6A, B); seminal groove running entirely mesally along fermorite, “postfemoral” portion demarcated by a lateral sulcus. Process e prominent, stout, expanded apically, about as long as solenomere (sl), denticulate near middle. Solenomere (sl) thick, slightly coiled apically.

Remarks. This species appears to be quite widespread. It has been found in several places in eastern Thailand to southern Laos ( Fig. 20 ). The animals reveal the same morphological characters in all populations except the population from Ban Xanapho, Laos, in which the legs and antennae are carmine to light pink while their bodies larger (length 45.8–47.2 mm). However, the width of midbody pro- and metazonae lies well within the species’ variation range (3.9 and 4.7 mm, 4.2 and 4.9 mm, respectively), so the Laotian population is attributed to this species.

Figures

FIGURE 1. Enghoffosoma zebra sp. n., habitus, live coloration. A: holotype. B: male paratype from Numtip Temple. C: male paratype from Tadtone. D: male paratype from Ban Xanapho.

FIGURE 2. Enghoffosoma zebra sp. n., holotype (A – I), male paratype from Numtip Temple (J, K), male paratype from Ban Xanapho (L). A, B: anterior part of body, dorsal and lateral views, respectively. C: segments 10 and 11, dorsal view. D: segments 9 – 11, lateral view. E – G: posterior part of body, lateral, dorsal and ventral views, respectively. H, I: sternal cones between coxae 4, subcaudal and sublateral views, respectively. J, K: segments 10 and 11, dorsal view. L: anterior part of body, dorsal view.

FIGURE 3. Enghoffosoma zebra sp. n., holotype. A – C: right gonopod, lateral, mesal and submesal views, respectively. Scale bar: 0.5 mm. C: sterna of segment 10. E: leg of segment 10. Drawn not to scale. Designations explained in text.

FIGURE 4. Enghoffosoma zebra sp. n., male paratype from Numtip Temple (A, B), male paratype from Ban Xanapho (C, D). A, B: right gonopod, mesal and submesal views, respectively. C, D: right gonopod, mesal and submesal views, respectively. Scale bar: 0.5 mm. Designations explained in text.

FIGURE 5. Enghoffosoma zebra sp. n., holotype, right gonopod. A, B: lateral and mesal views, respectively. C – F: distal part of left gonopod, sublateral, submesal, subcaudal and suboral views, respectively. Scale bar: 0.2 mm.

FIGURE 6. Enghoffosoma zebra sp. n., male paratype from Numtip Temple (A, B), male paratype from Ban Tadtone (C, D). A, B: right gonopod, mesal and lateral views, respectively. C, D: right gonopod, mesal and lateral views, respectively. Scale bar: 0.2 mm.

FIGURE 7. Enghoffosoma zebra sp. n., male paratype from Ban Xanapho, right gonopod. A, B: lateral and mesal views, respectively. C – F: distal part of left gonopod, lateral, mesal, subcaudal and suboral views, respectively. Scale bar: 0.2 mm.

FIGURE 20. Distribution of Enghoffosoma species. Open diamond: Enghoffosoma longipes Golovatch, 2011. Open square: Enghoffosoma spinipleurum (Carl, 1941). Open triangle: Enghoffosoma zebra sp. n. Open circle: Enghoffosoma funda sp. n. Asterisk: Enghoffosoma lanceolatum sp. n. and E. anchoriforme sp. n. Crossed square: Enghoffosoma bispinum sp. n.