Tylopus retusus, Likhitrakarn & Golovatch & Panha, 2016

Likhitrakarn, Natdanai, Golovatch, Sergei I. & Panha, Somsak, 2016, The millipede genus Tylopus Jeekel, 1968 (Diplopoda, Polydesmida, Paradoxosomatidae), with a key and descriptions of eight new species from Indochina, European Journal of Taxonomy 195, pp. 1-47 : 14-17

publication ID	https://doi.org/ 10.5852/ejt.2016.195
DOI	https://doi.org/10.5281/zenodo.3852404
persistent identifier	https://treatment.plazi.org/id/03EB5A00-FFF2-7D78-ACE8-D6A5FC149C4B
treatment provided by	Valdenar
scientific name	Tylopus retusus
status	sp. nov.

Treatment

Tylopus retusus View in CoL sp. nov.

urn:lsid:zoobank.org:act:40D74A7C-61D7-442B-B388-3868C47102C5

Figs 10 – 11 View Fig View Fig , 26 View Fig

Diagnosis

Distinguished by its relatively small body with four transverse rows of setae forming no regular pattern of setation; in gonopod structure it is similar to T. haplorugosus Golovatch & Enghoff, 1993 , but differs in process h being rather short, slightly flattened, blunt, coupled with the solenophore being strongly coiled.

Etymology

To emphasize the blunt tip of process h; adjective.

Material examined

Holotype

LAOS: Ƌ, Muang Xay City, Xay , Oudomxai, 20°41'00" N, 101°59'05" E, ca 640 m a.s.l., mango garden, 14 Oct. 2014, leg. C. Sutcharit & R. Srisonchai ( CUMZ).

GoogleMaps

Paratype

LAOS: 1 ♀, Khoua, Phongsaly, ca 835 m a.s.l., 21°11'55" N, 102°06'40" E, forest near road, 15 Oct. 2014, leg. C. Sutcharit & R. Srisonchai ( CUMZ).

Description

MEASUREMENTS AND COLOUR. Length 16.3 (Ƌ) or 20.4 mm (♀), width of midbody pro- and metazonae 1.12 and 2.07 mm (Ƌ) or 2.7 and 3.7 mm (♀), respectively. Live coloration light brown ( Fig. 10A View Fig ); prozonae dark brown; paraterga, antennae, head and legs light brown to yellow-brown. Coloration of alcohol material after one year of preservation faded to light brown to yellow-brown; paraterga, antennae, head, legs and venter light brown to light yellow ( Fig. 10 View Fig B–J).

HEAD. Clypeolabral region and vertex sparsely setose, epicranial suture distinct. Antennae ( Fig. 10A, B View Fig ) rather short and stout, antennomeres 2–6 subequal in length, reaching body segment 3 (Ƌ, ♀) when stretched dorsally. In width, head <segment 3 <4 <collum <segments 5–15; thereafter body gently and gradually tapering. Collum with three transverse rows of setae: 6+6 anterior, 4+4 intermediate and 6+6 posterior; a small lateral incision at about midway; caudal corner very broadly rounded, paraterga declined ventrad, slightly produced behind rear tergal margin.

BODY. Tegument smooth and shining, prozonae finely shagreened, metaterga leathery, finely rugulose ( Fig. 10B, D, F View Fig ); surface below paraterga roughly microgranulate ( Fig. 10C, E, H View Fig ). Postcollum metaterga with four transverse rows of setae forming no regulated pattern of setation, anterior row with the most dense setae growing increasingly dense towards segment 19 ( Fig. 10B, D, F View Fig ). Tergal setae long and slender, about 2/3 as long as metaterga. Axial line well visible on metazonae, traceable also on prozonae. Paraterga strongly developed ( Fig. 10 View Fig B–H), especially so in Ƌ, 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, starting with segment 16 extending increasingly behind rear tergal margin ( Fig. 10F, H View Fig ). Paraterga 2 and 3 with two evident incisions at lateral edge ( Fig. 10B View Fig ). Following poreless segments with two similar incisions; pore-boring segments with one, often setigerous incision lying in front of pore ( Fig. 10D, E View Fig ). Calluses of 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 usually distinct ( Fig. 10B, D, F View Fig ), slightly incomplete on segment 19, complete on segments 5–18, narrow, undulate, shallow, not reaching bases of paraterga, beaded at bottom. Stricture between pro- and metazonae evident, wide and deep, beaded at bottom down to base of paraterga ( Fig. 10B, D – F View Fig ). Pleurosternal carinae complete crests with a sharp caudal tooth on segments 2–7 (Ƌ) or 2–4 (♀), thereafter increasingly reduced to a small tooth until segment 15 (Ƌ) or 13 (♀), missing more caudally. Epiproct ( Fig. 10 View Fig F–H) conical, flattened dorsoventrally, with two evident, large, rounded apical papillae; tip subtruncate; lateral preapical papillae small, lying close to tip. Hypoproct ( Fig. 10G View Fig ) roundly subtrapeziform, setigerous knobs at caudal edge small and well-separated.

STERNA. Densely setose, with a small cone caudally near each coxa, rear cones being a little larger than fore ones ( Fig. 11E View Fig ); two small, rough, fully separated, setose cones between Ƌ coxae 4 ( Fig. 10I, J View Fig ). Legs rather long and slender, midbody ones ca 1.2–1.3 (Ƌ) or 0.9–1.0 (♀) as long as body height; all male legs until segment 16 with tarsal brushes, prefemora not swollen; prefemora, femora and tibiae with ventral microgranulations; femora, tibiae and tarsi each with an evident adenostyle (tubercle) medially ( Fig. 11F – G View Fig ).

GONOPOD. Rather simple ( Fig. 11 View Fig A–D); coxa a little curved caudad, sparsely setose distoventrally. Femorite slightly curved and stout, with an evident mesal groove and a clear distolateral sulcus demarcating a postfemoral part; lobe l evident, rounded, with process h rather short, slightly flattened, blunt; solenophore (sph) strongly coiled, devoid of processes, pointed.

Remark

This species was found in a mango plantation in Muang Xay City.