Glyphiulus steineri, Likhitrakarn & Jeratthitikul & Jirapatrasilp & Wesener, 2024

Likhitrakarn, Natdanai, Jeratthitikul, Ekgachai, Jirapatrasilp, Parin & Wesener, Thomas, 2024, Integrated taxonomy of three new species of Glyphiulus Gervais, 1847 (Diplopoda, Spirostreptida, Cambalopsidae) from Laos, Raffles Bulletin of Zoology 72, pp. 42-61 : 50-53

Glyphiulus steineri , new species

( Figs. 3 , 4 )

Holotype. Male ( ZFMK MYR-6203 ( TW408 )), Laos, Khammouan Province, Tham Nam Ock , 17°35′24.11″N, 105°50′7.26″E, 3 March 2016, leg. H. Steiner.

Etymology. To honour the German collector and biospeleologist Helmut Steiner, an active explorer of the caves of Laos, noun.

Diagnosis. This new species is especially similar to G. pseudocostulifer , new species, with which it shares the following diagnostic characters: the unique carinotaxic formulae of postcollum rings, coupled with anterior and posterior gonopod structural details. It differs from G. pseudocostulifer , new species, by the carinotaxic formula of the midbody rings: 2/2+I/i+3/3/3+I/i+2/2 ( Fig. 3A, B, D–H ) (vs. 2+I/i+3/3+I/i+2 ( Fig. 1A, B, D–H )), coupled with the apicomesal processes (d) on the anterior gonopods being broader and stout ( Fig. 4H, I ) (vs. longer and slender ( Fig. 2H, I )), and with an evident, swollen, rounded apicolateral process (ap) ( Fig. 4H, I ) (vs. smooth without apicolateral process ( Fig. 2H, I )), and the axe-shaped tip of the flagellum process (f) on the posterior gonopods ( Fig. 4J, K ) (vs. pointed tip ( Fig. 2J, K )).

Description. Length of holotype 34.5 mm; midbody rings round in cross-section ( Fig. 3F ), their width (horizontal diameter) and height (vertical diameter) being similar; width of holotype 1.4 mm.

Colouration in alcohol ( Fig. 3 ), after seven years of preservation, uniformly brownish to yellowish, metazonites usually dark brownish ( Fig. 3A, B, D, E, H ). Head light brown yellowish, vertex dark brown ( Fig. 3A, C ). Antennae, venter, and legs yellowish to pallid ( Fig. 3A–C, E–G, I ). Eyes blackish ( Fig. 3A, C ).

Body with 56p+2a+T rings (holotype). Eye patches transversely ovoid, each composed of 3 or 4 rather flat ommatidia in a single longitudinal row ( Fig. 3A, C ). Antennae long and filiform ( Figs. 3A–C , 4B ), reaching beyond ring 6 laterally, antennomeres 5 and 6 each with a small distoventral group or corolla of bacilliform sensilla ( Fig. 4B ). Gnathochilarium with a clearly separated promentum ( Fig. 4A ).

Head width = ring 2 <collum = midbody ring (close to 8th to 10th)> ring 3 = 6> 4 = 5 <7 <8 = 10; body abruptly tapering towards telson on a few posterior-most rings ( Fig. 3H ). Postcollar constriction rather evident ( Fig. 3B ).

Collum with 6+6 low longitudinal crests starting from anterior edge, but both median crests interrupted in about caudal 1/2–1/3, being replaced there by similar 1+1+1 crests; carinotaxy formula 1–5+6a+pc+ma ( Fig. 3A–C ).

Following metaterga very strongly crested ( Fig. 3A–H ), especially from ring 5 on, whence porosteles commence ( Fig. 3A, B ), each tubercle higher and more pointed tip ( Fig. 3D, E ), but smaller tubercles in their stead on legless rings in front of telson due to loss of ozopores ( Fig. 3G, H ). Porosteles large, conical, triangle, directed caudolaterad, higher than wide, ozoporiferous crests distinctly divided into three, their frontal porosteles half of metatergal height ( Fig. 3D–H ). Carinotaxy formulae 2+I/i+3+I/i+2 on rings 2 and 3, as well as on the last 1 or 2 leg-bearing and legless rings ( Fig. 3A, B, G, H ); midbody rings showing all dorsal crests subdivided transversely (carinotaxy formulae 2/2+I/i/ i+3/3/3+I/i/i+2/2) and sharper, lateral crests especially sharp ( Fig. 3D–H ).

Tegument rather smooth and shining throughout, quite sparsely alveolate-areolate ( Fig. 3A, B, D, E, G, H ). Fine longitudinal striations in front of stricture between pro- and metazonae, remaining surface of prozonae very delicately shagreened ( Fig. 3D, E ). Metatergal setae absent. Rings 2 and 3 each with long pleural flaps. Epiproct ( Fig. 3G–I ) simple, regularly rounded caudally, faintly convex medially, with a median tubercle and a following rounded ridge in caudal part and an evident axial rib dorsally. Paraprocts regularly convex, each with premarginal sulci medially and a row of sparse setae at medial margin ( Fig. 3I ). Hypoproct smooth and straight caudally, with 1+1 strongly separated setae near caudal margin ( Fig. 3I ).

Ventral flaps behind gonopod aperture on male ring 7 evident, distinguishable as rather high swellings with rounded flaps bent abruptly caudad ( Fig. 3C ).

Legs long and slender, on midbody rings nearly as long as body diameter ( Figs. 3A, C, F, G, H , 4G ). Claw at base with an evident accessory claw about 1/3–1/4 the length of main claw ( Fig. 4G ).

Male leg pair 1 highly characteristic ( Fig. 4C, D ) in showing nearly fully developed, 5-segmented telopodites and a pair of rather small, subdigitiform, medially contiguous, but apically diverging coxal processes with a group of few strong setae at base.

Male leg pair 2 nearly normal, claw long and slender, anteriorly, coxa somewhat reduced, and femur abbreviated on frontal face; penes broad, subtrapeziform, truncate apically, fused at base ( Fig. 4E ).

Male leg pair 3 modified, coxa especially slender and elongate ( Fig. 4F ).

Anterior gonopods ( Fig. 4H, I ) with a typical shield-like coxosternum, the latter moderately microsetose in anterior and medial parts on caudal face ( Fig. 4I ), with a long, high, digitiform, apicomesal process (dp) and an obvious apicolateral process (ap). Telopodite typical, rather small, slender, movable, 1-segmented, lateral in position, with 2 or 3 strong apical setae and a field of microsetae at base ( Fig. 4I ). Posterior gonopods ( Fig. 4J, K ) compact, broadly subquadrate, with a long, stout flagellum process (f), axe-shape tip ( Fig. 4J, K ); lamelliform lobe (l) higher than caudal piece of coxite, membranous, wrinkled frontolaterally, with an apical field of coniform microsetae caudally ( Fig. 4J ). Coxite smooth, each mediolateral part of coxite with 14–16 strong, long and curved setae ( Fig. 4J, K ).

Figures

Fig. 3. Glyphiulus steineri, new species, male holotype (ZFMK MYR6203). A–C, anterior part of body, lateral, dorsal, and ventral views, respectively; D, E, midbody rings, dorsal and lateral views, respectively; F, cross-section of a midbody ring; G–I, posterior part of body, lateral, dorsal, and ventral views, respectively.

Fig. 4. Glyphiulus steineri, new species, male holotype (ZFMK MYR6203). A, gnathochilarium, ventral view; Bm antenna, lateral view; C, D, leg pair 1, oral and caudal views, respectively; E, leg pair 2, caudal view; F, leg pair 3, caudal view; G, midbody leg; H, I, anterior gonopods, oral and caudal views, respectively; J, K, posterior gonopods, caudal and oral views, respectively. Abbreviations: ap, apicolateral process; dp, apicomesal processes; f, flagellum process; l, lamelliform lobe. Scale bar: A–G 0.1 mm, H–K 0.02 mm.

Fig. 1. Glyphiulus pseudocostulifer, new species, male holotype (ZFMK MYR10009A). A–C, anterior part of body, lateral, dorsal, and ventral views, respectively; D, E, midbody rings, dorsal and lateral views, respectively; F, cross-section of a midbody ring; G–I, posterior part of body, lateral, dorsal, and ventral views, respectively.

Fig. 2. Glyphiulus pseudocostulifer, new species, male holotype (ZFMK MYR10009A). A, gnathochilarium, ventral view; B, C, leg pair 1, oral and caudal views, respectively; D, leg pair 2, caudal view; E, leg pair 3, caudal view; F, midbody leg; G, antenna, lateral view; H, I, anterior gonopods, oral and caudal views, respectively; J, K, posterior gonopods, oral and caudal views, respectively. Abbreviations: ap, apicolateral process; dp, apicomesal processes; f, flagellum process; l, lamelliform lobe. Scale bar: A–G 0.1 mm, H–K 0.02 mm.