Tylopus monticola, Likhitrakarn & Golovatch & Srisonchai & Panha, 2021

Likhitrakarn, Natdanai, Golovatch, Sergei I., Srisonchai, Ruttapon & Panha, Somsak, 2021, Two new species of the millipede genus Tylopus Jeekel, 1968 from Shan State, Myanmar (Diplopoda, Polydesmida, Paradoxosomatidae), ZooKeys 1040, pp. 167-185 : 167

publication ID	https://dx.doi.org/10.3897/zookeys.1040.66209
publication LSID	lsid:zoobank.org:pub:910903D2-476A-439F-AC73-292D5B9A18C1
persistent identifier	https://treatment.plazi.org/id/FD497FBD-67B7-4171-9905-ED6D2011DF51
taxon LSID	lsid:zoobank.org:act:FD497FBD-67B7-4171-9905-ED6D2011DF51
treatment provided by	ZooKeys by Pensoft
scientific name	Tylopus monticola
status	sp. nov.

Treatment

Tylopus monticola sp. nov. Figs 1A View Figure 1 , 2 View Figure 2 , 3 View Figure 3 , 4 View Figure 4

Material examined.

Holotype: Myanmar - Shan State • ♂; Taunggyi District, near Montawa Cave ; elev. 1204 m; 20°45'15.9"N, 97°01'03.4"E; 21 Sep. 2016; J. Sutcharit, R. Srisonchai leg.; CUMZ GoogleMaps . Paratypes: Myanmar - Shan State • 3 ♀♀; same collection data as holotype; CUMZ GoogleMaps • 1 ♀; same collection data as holotype; ZMUM GoogleMaps • 3 ♀♀; near Aye Say Tee Cave ; elev. 1583 m; 20°47'29.5"N, 97°03'01.6"E; 21 Sep. 2016; J. Sutcharit, R. Srisonchai leg.; CUMZ GoogleMaps • 1 ♂; Parpant area , outside the cave; elev. 1159 m; 20°15'03.7"N, 97°14'23.9"E; 23 Sep. 2016; J. Sutcharit, R. Srisonchai leg.; CUMZ GoogleMaps • 1 ♂; same collection data as previous; ZMUM GoogleMaps .

Diagnosis.

Using the latest key to Tylopus species ( Likhitrakarn et al. 2016), as well as the information concerning all 12 congeners described since ( Golovatch et al. 2016; Golovatch 2018, 2019, 2020; Golovatch and Semenyuk 2018), T. monticola sp. nov. keys out to T. rugosus Golovatch & Enghoff, 1993 on account of the particularly strong similarities in the gonopodal structure (Fig. 8 View Figure 8 ). Thus, even though they both share most of the somatic and gonopodal features, the new species differs in the large and long process z with a serrate edge along the dorsal margin, which protrudes beyond the apicolateral lobe (l) (Figs 3B-D View Figure 3 , 4A, B View Figure 4 ) (vs. smaller and not protruding beyond l) (Fig. 8B, C View Figure 8 ), all ♂ legs with the prefemora swollen laterally except for leg 1 (vs. except for legs 1 and 2), coupled with the pleurosternal carinae complete crests with an evident, sharp, caudal denticle produced past the rear tergal margin on segments 4-7, gradually decreasing in size until segments 15(16) (♂) or 13(12) (♀) (Fig. 2B, D, E View Figure 2 ) (vs. same, but gradually decreasing in size until segment 18).

Description.

Length of holotype ca 30 mm; adult paratypes 29-31 (♂) or 32-35 mm (♀), width of midbody pro- and metazonae of holotype, 2.4 and 3.6 mm; adult paratypes 2.4-2.5 and 3.4-3.7 mm (♂) or 2.9-3.5 and 3.7-4.5 mm (♀), respectively.

Colouration of live animals dark brown (Fig. 1A View Figure 1 ); calluses of paraterga, venter and legs lighter brown; colouration of alcohol material after two years of preservation faded to dark brown; head, antennae and tip of epiproct light brown, calluses of paraterga yellowish brown to pallid, venter and legs light brown to light yellowish (Fig. 2 View Figure 2 ).

Clypeolabral region and vertex sparsely setose, epicranial suture distinct. Antennae short (Figs 1A View Figure 1 , 2A, B View Figure 2 ), reaching body segment 3 (♂) or 2 (♀) when stretched dorsally. In width, head <segment 3 <4 <5 <6 <collum <segment 2 <7-16 (♂, ♀); thereafter body gently and gradually tapering. Collum with three transverse rows of strong setae: 3+3 anterior, 2+2 intermediate, and 3+3 posterior; a small lateral incision near midway; caudal corner of paraterga rounded, slightly declined ventrad, not produced past rear tergal margin (Fig. 2A, B View Figure 2 ).

Tegument rather smooth and shining, prozonae very finely shagreened, metaterga mainly smooth, but often rugulose; surface below paraterga finely microgranulate (Fig. 2A-F View Figure 2 ). Postcollum metaterga with two transverse rows of rather long setae: 2+2 in anterior and 3+3 in posterior row, the latter often abraded, but then readily traceable as insertion points. Tergal setae long, strong, slender, about 1/3 metatergal length. Axial line visible both on pro- and metazonae.

Paraterga strongly developed (Fig. 2A-F View Figure 2 ), especially well so in ♂, subhorizontal, slightly upturned posteriorly, always lying high, at upper 1/3 of midbody height, but remaining below dorsum; anterior edge well-developed, mostly regularly rounded and narrowly bordered, fused to callus; caudal corner narrowly rounded, extending increasingly past rear tergal margin, especially strongly so on segments 15-19; in segments 16-19, tips strongly curved mesad, posterior edge slightly oblique (Fig. 2A, C, F View Figure 2 ); paraterga very thin blunt blades in lateral view, a little thicker only on pore-bearing segments (Fig. 2D View Figure 2 ). Calluses on paraterga delimited by a sulcus only dorsally. Paraterga 2 broad, lateral edge with three evident incisions: one in anterior 1/3, one at midway, and one at posterior 1/3; anterior incision particularly evident. Paraterga 3 and 4 with two small incisions at lateral edge (Fig. 2A View Figure 2 ), one in anterior 1/3, the other at posterior 1/3; anterior incision also particularly evident. Lateral edge of paraterga of following segments with two small incisions, one in anterior 1/3, the other at midway, caudal incision being smaller in pore-bearing segments (Fig. 2C View Figure 2 ). Ozopores evident, lateral, lying in an ovoid groove at about 1/3 metatergal length in front of posterior edge of metaterga (Fig. 2D View Figure 2 ). Transverse sulcus usually distinct (Fig. 2A, C, F View Figure 2 ), slightly incomplete on segment 18, complete and clearly visible on metaterga 5-17, deep, reaching the bases of paraterga, arcuate, faintly beaded at bottom. Stricture between pro- and metazonae narrow, shallow, beaded at bottom down to base of paraterga (Fig. 2A, C, F View Figure 2 ). Pleurosternal carinae complete crests on segment 2-3(4) (Fig. 2B View Figure 2 ), with an evident and sharp denticle caudally on segments 4(5)-7 (♂, ♀), thereafter increasingly well reduced and remaining only a small sharp caudal tooth until segment 15(16) (♂) or 13(12) (♀), thereafter missing (Fig. 2B, D, E View Figure 2 ). Epiproct (Fig. 2E-G View Figure 2 ) conical, flattened dorsoventrally, subtruncate, with two evident apical papillae directed caudally, both pointed at tip; pre-apical papillae evident, lying close to tip. Hypoproct subtrapeziform (Fig. 2G View Figure 2 ), small setiferous knobs at caudal edge well-separated and evident.

Sterna densely setose, without modifications (Fig. 2G View Figure 2 ); cross-impressions shallow; a deeply notched sternal lobe between ♂ coxae 4 (Fig. 2H, I View Figure 2 ). Legs long and slender, midbody ones ca 1.4-1.5 (♂) or 0.9-1.0 (♀) as long as body height; all ♂ legs except leg 1 with prefemora swollen laterally; femora and tibiae with particularly dense setae and ventral microgranulations; legs on segments 7-18 with an evident adenostyle (tubercle) medially on each postfemur and tibia (Fig. 4C View Figure 4 ); tarsal brushes absent.

Gonopods (Figs 3 View Figure 3 , 4A, B View Figure 4 ) simple; coxite slightly curved caudad, sparsely setose distoventrally. Prefemorite densely setose, about 1/3 as long as femorite + “postfemoral” part. Femorite rather stout, expanded distad, suberect, showing a distinct mesal groove/hollow (g); apicolateral lobe (l) simple; process z large and long, serrate along dorsal margin and protruding beyond apicolateral lobe (l); process h short and stout, suberect, with a narrowly rounded tip; solenophore long and slender, typically coiled, tip subtruncate.

Name.

To emphasize the habitats where this new species was discovered; " Tylopus monticola " meaning a mountain-dweller or a highlander; noun in apposition.

Remark.

The species was found quite far away (about 120 air-km) from the type locality of the most similar species, T. rugosus Golovatch & Enghoff, 1993 (Fig. 9 View Figure 9 ). Both new species described here have been found to occur syntopically.