Tylopus acuminatus sp. nov.

urn:lsid:zoobank.org:act: C0DB482F-EE58-4385-9733-7D2E724DEFED

Figs 12–15, 26

Diagnosis

Very similar to T. jeekeli Golovatch & Enghoff, 1993 and T. parajeekeli Likhitrakarn, Golovatch, Prateepasen & Panha, 2010, especially in its gonopod conformation, but differs in process h being higher and more strongly flattened, pointed, while the sternal lobe between ♂ coxae 4 linguiform and larger.

Etymology

To emphasize the acuminate processes h on the gonopod; adjective.

Material examined

Holotype

LAOS: ♂, Ban Sin Chai, Boun Neua, Phongsali, 21°31'50" N, 101°51'45" E, ca 820 m a.s.l., 15 Oct. 2014, leg. C. Sutcharit & R. Srisonchai (CUMZ).

Paratypes

LAOS: 1 ♂, 1 ♀, Phuthalang forest protected area, Boun Neua, Phongsali, 21°37'30" N, 101°55'55" E, ca 1125 m a.s.l., 16 Oct. 2014 (CUMZ); 1 ♂, 2 ♀♀, Phufa, Boun Neua, Phongsali, 21°41'05" N, 102°06'35" E, ca 1470 m a.s.l, 16 Oct. 2014 (CUMZ); 1 ♀, near Ban Borkhun, Boun Neua, Phongsali, 21°27'57" N, 101°47'20" E, ca 880 m a.s.l., 18 Oct. 2014 (CUMZ); 1 ♀, Khoua, Phongsali, 21°11'55" N, 102°06'40" E, ca 840 m a.s.l., 15 Oct. 2014 (CUMZ); 1 ♂, 1 ♀ (NHMW), 1 ♂ (ZMUM ρ3059), Ban Na Thong, Namo, Oudomxay, 20°52'25" N, 101°47'00" E, ca 650 m a.s.l., 14 Oct. 2014; 1 ♂, Phagneung Phoukulom Waterfall, Sing, Luang Namtha, 21°07'15" N, 101°14'40" E, ca 900 m a.s.l., 13 Oct. 2014, all leg. C. Sutcharit & R. Srisonchai (ZMUC).

Description

MEASUREMENTS AND COLOUR. Length 24.5–31.6 (♂) or 24.3–31.5 mm (♀), width of midbody pro- and metazonae 1.98–2.6 and 2.95–3.6 mm (♂) or 2.7–2.9 and 3.1–4.2 mm (♀), respectively. Live coloration dark brown (Fig. 12A); antennae and epiproct light brown; legs yellow-brown. Coloration of alcohol

material after one year of preservation faded to brown to yellow-brown; head, antennae, epiproct light brown to yellow-brown, legs and venter yellow-brown to light yellow (Fig. 12 B–J).

HEAD. Clypeolabral region densely, vertex sparsely, setose; epicranial suture distinct. Antennae (Fig. 12A) short, surpassing body segment 2 (♂, ♀) when stretched dorsally. In width, head <segment 3 <collum <segment 4 <2 <5–16 (♂), or head <segment 3 <4 <collum <segment 2 <5–16 (♀); thereafter body gently and gradually tapering. Collum with three transverse rows of setae: 4+4 anterior, 1+1 intermediate and 2+2 posterior paraterga declined ventrad, with a small lateral incision at about midway; caudal corner very broadly rounded, not surpassing rear tergal margin (Fig. 12C).

BODY. Tegument smooth and shining, prozonae finely shagreened, metaterga smooth and leathery (Fig. 12B, D, F); surface below paraterga microgranulate (Fig. 12C, E, H). Postcollum metaterga with an anterior transverse row of 2+2, mostly abraded setae; posterior row barely traceable as 4+4 insertion points, these being better visible on segments 17–19 (Fig. 12F). Tergal setae simple and slender, about 2/3 as long as metaterga. Axial line traceable on prozonae and anterior halves of metazonae. Paraterga well-developed (Fig. 12 B–F, H), especially so in ♂, set rather high (at upper 1/3 of body height), slightly upturned, but lying below dorsum; anterior edge broadly rounded and narrowly bordered, fused to callus; caudal corner very narrowly rounded, drawn behind tergal margin, increasingly protruding and pointed starting with segment 16 (Fig. 12F, H). Paraterga 2 with two evident incisions at lateral edge in anterior 1/3. Paraterga 3 and 4 each with two similar incisions at lateral edge, one in anterior 1/3, the other about the middle. Following paraterga each with one evident lateral incision in anterior 1/3 and, in pore-bearing segments, a very small denticle in the middle (Fig. 12B, D, F). Calluses on paraterga delimited by a sulcus both dorsally and ventrally. Ozopores evident, lateral, lying in an ovoid groove at about 1/3 of metatergal length in front of posterior edge of metaterga. Transverse sulcus evident on metaterga 5–17, incomplete on metaterga 18, narrow, line-shaped, rather deep, ribbed at bottom, not reaching bases of paraterga (Fig. 12B, D, F). Stricture between pro- and metazonae evident, wide and deep, ribbed at bottom down to base of paraterga (Fig. 12B, D – F). Pleurosternal carinae complete crests with a sharp caudal tooth on segments 2 and 3 (♂, ♀), increasingly reduced and remaining a strong, sharp, caudal tooth on segments 4–8, retained as a small sharp tooth on segments 9–16, a minute tooth on segment 17 (♂), or an evident, sharp, caudal tooth on segments 4–15, then remaining a small rounded tooth on segment 16, thereafter missing (♀) (Fig. 12C, E, H). Epiproct (Fig. 12 F–H) conical, flattened dorsoventrally, with two evident, rounded, apical papillae; tip subtruncate; lateral pre-apical papillae evident, lying close to tip. Hypoproct (Fig. 12G) roundly subtrapeziform, setigerous knobs at caudal edge small and well-separated.

STERNA. Moderately setose and densely microtuberculate; cross-impressing shallow; an entire, linguiform, sternal lobe between ♂ coxae 4 (Fig. 12I – J). A paramedian pair of conspicuous ridges in front of gonopod aperture. Legs rather long and slender, midbody ones ca 1.2–1.3 (♂) or 1.0–1.1 (♀) as long as body height; ♂ legs with prefemora distinctly swollen laterally, acropodites with particularly dense setae ventrally (Fig. 13C), but tarsal brushes absent.

GONOPOD. Rather simple (Figs 13A – B, 14 – 15); coxa slightly curved caudad, sparsely setose distoventrally. Femorite slightly curved and stout, with an evident mesal groove and a clear distolateral sulcus demarcating a postfemoral part; process h prominent, evidently curved, pointed, with a small, but evident dorsal tooth and sometimes with a small ventral denticle (Fig. 13A – B); spine z pointed, sometimes small (Fig. 15G); solenophore (sph) large, expanded, flattened and typically coiled.

Remark

This species shows slight variations in gonopod structure, process h often being rather narrow to slightly broader, while spine z small to slightly broader (Fig. 15).