Glyphiulus promdami, 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/31975FDC-B9BF-4130-9BE3-B06B9C0921EE

taxon LSID

lsid:zoobank.org:act:31975FDC-B9BF-4130-9BE3-B06B9C0921EE

treatment provided by

ZooKeys by Pensoft

scientific name

Glyphiulus promdami
status

sp. nov.

Glyphiulus promdami sp. nov.

Figs 3 View Figure 3 , 4 View Figure 4

Type material.

Holotype ♂: Thailand, Nan Province, Na Noi District, Tham Chetawan, 18°16'26"N, 100°34'43"E; 520 m a.s.l., 18.05.2018, S. Jantarit leg.; CUMZ-CAM169. Paratypes: 5 ♂, 5 ♀: same locality as holotype; CUMZ-CAM169; 1 ♂, 1 ♀: same locality as holotype; ZMUM; 1 ♂, 1 ♀: same locality as holotype; NHM-PSU; 1 ♂, 3 juv.: same Province, Na Muen District, Tham La-ong, 18°14'18"N, 100°34'55"E, 648 m a.s.l., 18.05.2018, S. Jantarit leg.; CUMZ-CAM170; 3 ♂, 2 ♀: Phrae Province, Rong Kwang District, Tham Pha Phrai Wan, 18°25'18"N, 100°28'10"E, 419 m a.s.l., 17.05.2019, S. Jantarit leg.; CUMZ-CAM166.

Name.

The species is so named to honour Mr. Rueangrit Promdam, a carcinologist and researcher at the Princess Maha Chakri Sirindhorn Natural History Museum of Prince of Songkla University (NHM-PSU), who is interested in cave fauna in the country and who has collected many millipedes, including this new species, from various Thai caves.

Diagnosis.

This new species seems to be particularly similar to G. subbedosae Likhitrakarn, Golovatch & Panha, 2017, from Laos ( Likhitrakarn et al. 2017), with which it shares the following diagnostic characters: body size, colour pattern and unique carinotaxic formulae, coupled with certain anterior and posterior gonopod structural details. It differs from G. subbedosae primarily by a uniformly yellow collum (Fig. 3A-C View Figure 3 ) (vs. its anterior half darker) and the median and lateral parts of the posterior gonopod coxite with 10-12 strong setae (Fig. 4K View Figure 4 ) (vs. six strong setae), coupled with the anterior gonopod coxosternum being moderately microsetose in the anterior and medial parts on the caudal face (Fig. 4H View Figure 4 ) (vs. only in medial part).

Description.

Length of holotype, 21.8 mm; adult paratypes 14.5-18.4 (♂) or 14.2-24.3 mm long (♀), juveniles 6.5-12.3 mm long; midbody rings round in cross-section (Fig. 5L View Figure 5 ), their width (horizontal diameter) and height (vertical diameter) being similar; width in holotype, 0.9 mm; in paratypes, 0.7-1.0 (♂), 0.8-1.1 (♀) or 0.5-0.7 mm (juveniles).

Coloration in alcohol (Fig. 3 View Figure 3 ), after three years of preservation, uniformly red-yellownish to grey-brown, dorsal crests and porosteles usually dark brownish (Fig. 3A, B, D, E, H View Figure 3 ). Head, collum, antennae and venter yellowish to pallid (Fig. 3A, C, E-G, I View Figure 3 ). Eyes blackish to brownish (Fig. 3A, C View Figure 3 ).

Body with 58p+1a+T rings (♂ holotype); paratypes with 35-58p+1-2a+T (♂), 39-51p+1-3a+T (♀) or 25-35+2-5a+T (juveniles). Eye patches transversely ovoid, each composed of 8-13 blackish, rather flat ocelli in three or four irregular longitudinal rows (Fig. 3A View Figure 3 ). Antennae short and clavate (Figs 3A, C View Figure 3 , 4A View Figure 4 ), extending past ring 3 laterally, antennomeres 5 and 6 each with a small distoventral group or corolla of bacilliform sensilla (Fig. 4A View Figure 4 ). Gnathochilarium with a clearly separated promentum (Fig. 4B View Figure 4 ).

In width, head = ring 4 = 5 <6 <7 <3 <midbody rings (close to 8th to 10th) <2 <collum; body abruptly tapering towards telson on a few posteriormost rings (Fig. 3B View Figure 3 ). Postcollar constriction very evident (Fig. 3B View Figure 3 ).

Collum nearly smooth, carinotaxic formula 1-6+7a+pc+ma (Fig. 3A-C View Figure 3 ), with 7+7 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 similarly strongly crested (Fig. 3A, B, D-H View Figure 3 ), especially from ring 5 on, whence porosteles commence (Fig. 3A, B View Figure 3 ), smaller tubercles in their stead on legless rings in front of telson due to loss of ozopores (Fig. 3G, H View Figure 3 ). Porosteles large, conical, round, directed caudolaterad, wider than high. 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. 3G, H View Figure 3 ). Carinotaxic formulae 3+I/i+3/3+I/i+3 on rings 2-4, as well as on the last one or two leg-bearing, and on legless rings (Fig. 3A, B, G, H View Figure 3 ); midbody rings showing mostly dorsal crests distinctly divided into two at about 1/3 metatergal height, each half rather evident and well rounded (carinotaxic formulae 3/3+I/i+4/3+I/i+3/3) and sharper, especially so lateral crests (Fig. 3D, E View Figure 3 ).

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

Ventral flaps behind gonopod aperture on ♂ ring 7 distinguishable as low swellings forming a bare transverse ridge.

Legs rather short, on midbody rings about half the length of ring height (Figs 3A, C, E-G View Figure 3 , 4G View Figure 4 ). Claw at base with an evident accessory spine about 1/3-1/4 the length of main claw (Fig. 4G View Figure 4 ).

♂ legs 1 highly characteristic (Fig. 4C, D View Figure 4 ) in being very strongly reduced, represented only by a sternum devoid of any median or paramedian structures, but carrying 1+1 strongly separated prongs, both evidently curved posteriad and bearing several strong setae, and rudimentary, 1-segmented leg vestiges at base on caudal face (Fig. 4C, D View Figure 4 ).

♂ legs 2 nearly normal (Figs 4E View Figure 4 ), prefemur somewhat reduced only anteriorly; penes broad, oblong-subtrapeziform, each with 3-5 strong setae distolaterally (Fig. 4E View Figure 4 ).

♂ legs 3 modified in having coxa especially slender and elongate (Fig. 4F View Figure 4 ).

Anterior gonopods (Fig. 4H, J View Figure 4 ) with a typical shield-like coxosternum, the latter moderately microsetose in anterior and medial parts on caudal face (Fig. 4H View Figure 4 ), with a high, digitiform, apicomesal process (d). Telopodite rather small, movable, 1-segmented, lateral in position, with two or three strong apical setae and a field of microsetae at base (Fig. 4H View Figure 4 ), moderately higher than adjacent lateral corner of coxosternum.

Posterior gonopods (Fig. 4J, K View Figure 4 ) compact, broadly subquadrate, micropapillate medially on oral face; coxite medio-apically with a long, plumose, apical flagellum (f) with evident spikes paramedially (Fig. 4J, K View Figure 4 ); lamelliform lobe (l) high, subquadrate, membranous, wrinkled frontolaterally, with an apical field of coniform microsetae laterally (Fig. 4K View Figure 4 ); each mediolateral part of coxite with 10-12 strong and curved setae (Fig. 4K View Figure 4 ).

Remarks.

The Glyphiulus granulatus -group currently encompasses 36 described species, including our new species ( Golovatch et al. 2007a, 2011a; Likhitrakarn et al. 2017; Liu and Wynne 2019). The new species is the fifth in this group to be reported from Thailand.

Three populations have been collected inside caves, with the longest distance of about 25 air-km between the collecting localities, and all show similar morphological characters as described above. Glyphiulus promdami sp. nov. fails to show any morphological adaptations to cave life and is considered here as a troglophilic species. It appears to have a rather narrow distribution, but has been found in a wide range of cave environments from the twilight (Tham Chetawan) to the dark and deep zones of the caves (all three caves). The temperature in the caves where the species was collected ranged between 24.2 and 29.8 °C, while the relative humidity was 70-94%. All populations were found to be quite large and associated with bat guano.