Tylopus corrugatus, Likhitrakarn, Natdanai, Golovatch, Sergei I. & Panha, Somsak, 2014

Likhitrakarn, Natdanai, Golovatch, Sergei I. & Panha, Somsak, 2014, Three new species of the millipede genus Tylopus Jeekel, 1968 from Thailand, with additional notes on the species described by Attems (Diplopoda, Polydesmida, Paradoxosomatidae), ZooKeys 435, pp. 63-91 : 64-68

Taxon classification Animalia Polydesmida Paradoxosomatidae

Tylopus corrugatus sp. n. Figs 1-3

Holotype.

♂ (CUMZ), Thailand, Chiang Mai Province, Chom Thong District, Doi Inthanon National Park, 1,700 m a.s.l., 18°31'55"N, 98°29'30"E, 20.12.2013, leg. N. Likhitrakarn & S. Chaiwong.

Paratypes.

2 ♂, 6 ♀, 2 juveniles (CUMZ), 1 ♂ (NHMW), same locality, together with holotype. 1 ♂, 1 ♀ (CUMZ), same locality, 25.01.2013, leg. N. Likhitrakarn.

Name.

To emphasize the clearly wrinkled postcollum metaterga.

Diagnosis.

Differs from congeners mainly in the very strongly developed paraterga with evident oblong ridges. Gonopod process h prominent, hook-shape, much longer than solenophore.

Description.

Length 15.5-18.2 (♂) or 16.5-21.0 mm (♀), width of midbody pro- and metazonae 1.50-1.70 and 1.95-2.15 mm (♂) or 1.55-2.0 and 2.0-2.5 mm (♀), respectively.

Coloration of live animals blackish-brown (Fig. 1A) with a pattern of contrasting light brown paraterga and posterior halves of midbody metaterga and epiproct, dark brown to light brown head, legs and antennae; coloration in alcohol faded after two months of preservation, paraterga, legs and epiproct being light brown to whitish; head to metazonae 3 blackish, thereafter metazonae with a light brown to whitish cross (Fig. 1B, D, F); venter and a few basal podomeres light brown to yellow-brown, legs increasingly darker brown distally (Fig. 1 B–J).

Clypeolabral region and vertex sparsely setose, epicranial suture distinct. Antennae moderately long (Fig. 1 A–C), reaching body segment 3 (♂) or 2 (♀) when stretched dorsally. In width, head <segment 3 = 4 <collum <2 <5-17 (♂, ♀); thereafter body gently and gradually tapering. Collum with three transverse rows of setae: 4+4 anterior, 3+3 intermediate and 5+5 posterior; a small incision laterally in posterior half; caudal corner of paraterga rounded, slightly declined ventrad, produced behind rear tergal margin (Fig. 1B, C).

Tegument leathery and shining, prozonae very finely shagreened, metaterga leathery, finely microgranulate and delicately rugulose; surface below paraterga finely mi crogranulate. Postcollum metaterga with two transverse rows of setae on evident oblong ridges: 2+2 in anterior (pre-sulcus) and 3+3 in posterior (post-sulcus) row, caudal row being more strongly developed than anterior one (Fig. 1 B–F, H); behind segment 10, metaterga with: 2+2 in anterior and 3(4)+3(4) in posterior row. Tergal setae long, strong, slender, about 1/3 of metatergal length. Axial line visible on metaterga. Paraterga very strongly developed (Fig. 1 B–F, H), especially well so in ♂, set at about 1/4 midbody height, mostly upturned, all lying high, but always below dorsum; shoulders well-developed, mostly rounded; caudal corner almost completely to fully pointed, extending increasingly beyond tergal margin, posterior edge mostly oblique, especially strongly so on segments 16-19 (Fig. 1F, H); paraterga very thin blunt blades in lateral view, a little thicker only on pore-bearing segments. Calluses on paraterga delimited by a sulcus only dorsally. Paraterga 2 broad, anterior edge angular, lateral edge with two evident incisions in anterior half; posterior edge slightly concave (Fig. 1B, C). Lateral edge of paraterga with evident incisions, one in anterior 1/3, the other at midway, caudal incision being smaller in pore-bearing segments. Ozopores evident, lateral, lying in an ovoid groove at about 1/3 in front of caudal corner. Transverse sulcus usually distinct (Fig. 1B, D, F), slightly incomplete on segment 19, complete on metaterga 4-18, deep, reaching bases of paraterga, clearly beaded at bottom. Stricture between pro- and metazonae wide, clearly ribbed at bottom down to base of paraterga (Fig. 1 B–E). Pleurosternal carinae complete crests with a sharp caudal tooth on segment 7 (♂, ♀), a small, caudal, mostly sharp tooth until segment 17 (♂) or 16 (♀), thereafter missing (Fig. 1C, E, H). Epiproct (Fig. 1F, G) conical, flattened dorsoventrally, with two strong apical papillae; tip subtruncate; pre-apical papillae evident, lying close to tip. Hypoproct roundly subtrapeziform (Fig. 1G), setiferous knobs at caudal edge well-separated and evident.

Sterna very densely setose, with a small cone caudally near each coxa, rear cones being a bit better developed than front ones (Fig. 2D); a deeply notched sternal lobe between ♂ coxae 4 (Fig. 1I, J). Legs moderately long and slender, midbody ones ca 1.0-1.2 (♂) or 0.9-1.1 times (♀) as long as body height, ♂ legs of segments 5-16 with an evident adenostyle (tubercle) on femur, postfemur, tibia and tarsus (Fig. 2 D–F); tarsal brushes present until ♂ legs 7.

Gonopods (Figs 2 A–C, 3) simple; coxa a little curved caudad, sparsely setose distoventrally. Prefemur densely setose, about 1/3 as long as femorite + “postfemoral” part. Femorite rather stout, expanded distad, slightly curved, showing a mesal groove; lobe l simple; process m apicoventral and spiniform; solenophore long and slender, typically coiled, tip subtruncate; process h strongly developed, curved and acute, longer than solenophore.