Glyphiulus longus, Likhitrakarn & Golovatch & Jantarit, 2021

Likhitrakarn, Natdanai, Golovatch, Sergei I. & Jantarit, Sopark, 2021, Two new species of the millipede genus Glyphiulus Gervais, 1847 (Diplopoda, Spirostreptida, Cambalopsidae) from caves in northern Thailand, ZooKeys 1056, pp. 173-189 : 173

publication ID

https://dx.doi.org/10.3897/zookeys.1056.71395

publication LSID

lsid:zoobank.org:pub:78A40C33-093B-4832-A725-F322377E2085

persistent identifier

https://treatment.plazi.org/id/B99F5675-C67F-4AA8-A777-6D987C2A975C

taxon LSID

lsid:zoobank.org:act:B99F5675-C67F-4AA8-A777-6D987C2A975C

treatment provided by

ZooKeys by Pensoft

scientific name

Glyphiulus longus
status

sp. nov.

Glyphiulus longus View in CoL sp. nov.

Figs 1 View Figure 1 , 2 View Figure 2

Type material.

Holotype ♂: Thailand, Nan Province, Pon, Thung Chang District, Tham Nam Lod, 19°25'13"N, 101°04'15"E, ca 1420 m a.s.l., 30.05.2018, S. Jantarit leg.; CUMZ-CAM171. Paratypes: 3 ♀: same locality as holotype; CUMZ-CAM171; 1 ♀: same locality as holotype; ZMUM; 1 ♀: same locality as holotype; NHM-PSU.

Name.

The species is so named to emphasize the long medial processes of the anterior and posterior gonopods; adjective.

Diagnosis.

This new species seems to be particularly similar to G. guangnanensis Jiang, Guo, Chen & Xie, 2018, from Yunnan Province, China ( Jiang et al. 2018), with which it shares the following diagnostic characters: very strong metatergal crests and unique carinotaxic formulae, coupled with certain anterior and posterior gonopod structural details. Glyphiulus longus sp. nov. differs from G. guangnanensis by the smaller body size, 22-26 mm long (vs. larger, 38-54 mm long) and the carinotaxic formula of the collum: 1+2a+3c+4-5+6c+7a+pc+ma (vs. 1a+2c+3-4+5c+6a+pc+ma) (Fig. 1A, B View Figure 1 ), coupled with ♂ legs 1 showing very strongly reduced telopodites (Fig. 2C, D View Figure 2 ) (vs. nearly normal telopodites), the apicomesal processes (d) on the anterior gonopods being very long and slender (Fig. 2G, H View Figure 2 ) (vs. shorter and digitiform), and the presence of a very long, medially densely plumose and stout flagellum process (f) on the posterior gonopods (Fig. 2I, J View Figure 2 ) (vs. slim and smooth flagellum process).

Description.

Length of holotype ♂, 23.5 mm; that of paratypes, 22.8-26.5 mm (♀); midbody segments round in cross-section (Fig. 1F View Figure 1 ), their width (horizontal diameter) and height (vertical diameter) being similar; width of holotype ♂, 1.0 mm, of ♀ paratypes, 0.9-1.2 mm.

Coloration in alcohol (Fig. 1 View Figure 1 ), after three years of preservation, uniformly red-brownish or dark castaneous brown to grey-brown, dorsal crests and porosteles usually dark brownish (Fig. 1A, B, D, E, H View Figure 1 ). Antennae and venter yellowish to pallid (Fig. 1A, C, E-G, I View Figure 1 ). Eyes blackish to brownish (Fig. 1A, C View Figure 1 ).

Body with 56p+2a+T rings/segments (♂ holotype); ♀ paratypes with 50-57p+2(1)a+T rings. Eye patches transversely ovoid, each composed of 2-5 rather flat ocelli in a single longitudinal row (Fig. 1A, C View Figure 1 ). Antennae short and clavate (Figs 1A, C View Figure 1 , 2A View Figure 2 ), extending past ring 3 laterally, antennomeres 5 and 6 each with a small distoventral group or corolla of bacilliform sensilla (Fig. 2A View Figure 2 ). Gnathochilarium with a clearly separated promentum (Fig. 2B View Figure 2 ).

In width, head = ring 2 <collum = midbody rings (close to 13th to 15th) <ring 4 = 5 <7 = 3 <8 = 10; body abruptly tapering towards telson on a few posteriormost rings (Fig. 1B View Figure 1 ). Postcollar constriction very evident (Fig. 1B View Figure 1 ).

Collum nearly smooth, carinotaxic formula 1+2a+3c+4-5+6c+7a+pc+ma (Fig. 1A-C View Figure 1 ), with 6+6 longitudinal crests starting from anterior edge, but both median crests interrupted in about caudal 2/3-3/4, being replaced there by similar 1+1+1 crests.

Following metaterga very strongly crested (Fig. 1A, B, D-H View Figure 1 ), especially from ring 5 on, whence porosteles commence (Fig. 1A, B View Figure 1 ), smaller tubercles in their stead on legless rings in front of telson due to loss of ozopores (Fig. 1G, H View Figure 1 ). Porosteles large, conical, round, directed caudolaterad, rather higher than wide (Fig. 1A, B, D-H View Figure 1 ). Midway metatergal crests on ring 5 distinctly divided into two at about 1/3 metatergal height, each half evident and well rounded, nearly undivided small tubercles in their stead in legless rings in front of telson (Fig. 1G, H View Figure 1 ). Carinotaxic formulae 2/2+I/i+3/3+I/i+2/2, all dorsal crests subdivided transversely and sharper, especially so lateral crests (Fig. 1B, D-H View Figure 1 ).

Tegument rather smooth, shining throughout (Fig. 1A, B, D-H View Figure 1 ). Fine longitudinal striations in front of stricture between pro- and metazonae, remaining surface of prozonae very delicately shagreened (Fig. 1D, E View Figure 1 ). Metatergal setae absent. Rings 2 and 3 each with long pleural flaps. Epiproct (Fig. 1G-I View Figure 1 ) simple, with a long dorsal crest in middle and small paramedian tubercles, regularly rounded caudally, faintly convex medially. Paraprocts regularly convex, each with premarginal sulci medially and a row of sparse setae at medial margin (Fig. 1I View Figure 1 ). Hypoproct transversely bean-shaped, slightly concave caudally, with 1+1 strongly separated setae near caudal margin (Fig. 1I View Figure 1 ).

Ventral flaps behind gonopod aperture on ♂ ring 7 barely distinguishable as low swellings forming no marked transverse ridge.

Legs short, on midbody rings about 2/3 length of body height (Figs 1A, C, E-G View Figure 1 , 2F View Figure 2 ). Claw at base with a very small accessory spine about 1/6 the length of main claw (Fig. 2F View Figure 2 ).

♂ legs 1 highly characteristic (Fig. 2C, D View Figure 2 ) in being very strongly reduced, 5-segmented telopodites and a pair of large, subdigitiform, medially contiguous, but apically diverging coxal processes with groups of long and strong setae at base.

♂ legs 2 nearly normal (Fig. 2E View Figure 2 ), claw long and slender; only anteriorly, prefemur somewhat reduced, and femur abbreviated on oral face; penes broad, rounded, each with four or five strong setae distolaterally (Fig. 2E View Figure 2 ).

♂ legs 3 missing, lost.

Anterior gonopods (Fig. 2G, H View Figure 2 ) with a typical shield-like coxosternum, the latter modestly microsetose on caudal face (Fig. 2G View Figure 2 ), on each side with a very long, slender, chopstick-shaped, apicomesal process (d) and an evident subsecuriform process (s), tip narrowly rounded. Telopodite rather small, stout, movable, 1-segmented, lateral in position, with three or four strong apical setae and a field of microsetae at base (Fig. 2G, H View Figure 2 ), about as long as adjacent lateral corner of coxosternum, but lower than paramedian processes (d) of coxosternum.

Posterior gonopods (Fig. 2I, J View Figure 2 ) compact, broadly subquadrate, micropapillate medially on oral face; with a very long, medially densely plumose and stout flagellum process (f) (Fig. 2I, J View Figure 2 ); lamelliform lobe (l) higher than caudal piece of coxite, membranous, smooth, with an apical field of coniform microsetae laterally (Fig. 2J View Figure 2 ); each median and lateral part of coxite with dense, strong and curved setae (Fig. 2J View Figure 2 ).

Remarks.

This new species belongs to the Glyphiulus javanicus -group which currently encompasses 32 described species ( Golovatch et al. 2007b, 2011b, 2012a; Likhitrakarn et al. 2017; Jiang et al. 2017, 2018, 2020). The above new congener is the second one in this group to be reported from Thailand. Due to the absence of any potential morphological cave adaptations, i.e., of a longer body, of a lighter coloration, and of elongated femora and tarsi of walking legs ( Liu et al. 2017), G. longus sp. nov. is only to be considered as troglophilic at most. The cave where the species was discovered is located at an elevation of ca 1420 m a.s.l. in Nan Province. The cave is rather narrow, hidden in a steep-sided doline in a riparian area. It consists of a streamway and a series of oxbow passages, with many links between these two parts to the cave. The areas where the cave was developed are surrounded by agricultural landscapes, i.e., cabbage and corn fields. The specimens were found on the cave floor with scattered bat guano and some debris brought in by the stream, ca 50 meters from the entrance. The temperature of the cave was 20.8-22.4 °C (mid-May), and the relative humidity was 85-90%. In the same cave and habitat, we also found Collembola ( Coecobrya sp. and Lepidocyrtus sp.), Formicidae ( Ponera sp.), Thelyphonida, mites and pseudoscorpions.