Halolaspis hypedon, Mašán, Peter & Halliday, Bruce, 2009

Mašán, Peter & Halliday, Bruce, 2009, Three new genera of the mite family Eviphididae (Acari: Mesostigmata), Zootaxa 2013, pp. 43-57 : 51-53

Halolaspis hypedon sp. nov.

(Figs 9−12, 15, 16, 20, 24)

Iphidosoma pratensis .⎯ Mašán, 1994a: 203.

Material examined. Holotype. Female, southwest Slovakia, Trnavská pahorkatina wold, Brunovce village, inundation zone of Váh river, 16 June 1991, pasture in degraded willow-poplar flood-plain forest (Salici - Populetum), subterranean brood chamber of Copris lunaris ( Coleoptera , Scarabaeidae ), 170 m a.s.l.. Paratypes. 1 female, same data except 23 June 1991; 1 female, same data except 30 June 1991. All these specimens were referred to as Iphidosoma pratensis Karg, 1965 , by Mašán (1994a).

Description (female). Dorsal idiosoma (Fig. 9). Idiosoma subglobular to hemispherical, length 665–730 µm (n = 3), suboval to lemon-shaped. Dorsal shield entire, 595–640 µm long, subrectangular, with subparallel lateral margins; posterior margin almost truncate or only moderately convex, shield narrowest at level of humeral angles, not completely covering dorsal surface, exposing strips of lateral and postdorsal cuticle. Dorsal shield bearing 30 pairs of setae, mostly smooth and needle-like, dorsocentral setae 19–25 µm long, somewhat shorter than lateral setae (26–36 µm) and markedly shorter than marginal setae (37–49 µm); j1 shortened, 8–12 µm long, columnar, with rounded tips; z1 short and fine; J4 short, 7–14 µm long, thickened, subcolumnar, with rounded tips. Pore-like structures small, barely visible, not hypertrophied. Lateral and posterior cuticle with coarse rugose-verrucose surface sculpture.

Ve n t r a l idiosoma (Fig. 10). Presternal platelets absent. Sternal shield ( Figs 11, 12 ) narrow, 115–125 µm long, longer than wide, surface smooth; anterior margin undulate, with two projecting lobes anterior to setae st1, antero-lateral corners obtuse; posterior margin straight or slightly concave, with rounded posterolateral corners. Shield with three pairs of short needle-like setae; setae st 1 27–30 µm long and inserted on a pair of small flat protuberances, setae st2 and st 3 31–34 µm long; second pair of sternal pores located very close to lateral margins of the shield. Endopodal platelets II subtriangular, free, well separated from sternal shield. Endopodal platelets III narrow, elongate, not connected with endopodals II. Metasternal platelets absent, metasternal setae st4 and associated pores inserted on soft cuticle between sternal and genital shields. Genital shield 72–82 µm wide, with rounded posterior margin, surface almost smooth, bearing a pair of genital setae close to its posterior margin; adjacent genital pores situated on soft cuticle beside genital setae. Anal shield suboval, 115–130 µm wide, slightly wider than long, with some sculptural lines on surface; anterior margin widely rounded; bearing three circum-anal setae and a pair of pores; anus situated close to anterior margin, without euanal setae and pore-like structures on anal valves. Anterior end of peritremes projecting beyond coxae I. Peritrematal shields well developed, anterior sections wide, overlapping onto dorsum and completely fused with anterolateral margins of dorsal shield, not fused with each other ventrally; poststigmatic sections narrow ( Fig. 16 ). Elongate metapodal and exopodal platelets IV present; a pair of narrow postgenital sclerites present between genital and anal shields. Ventral opisthosomal cuticle striated, with complex spiculatereticulate pattern of ornamentation and ten pairs of setae. Length of the longest ventral setae 55–65 µm. Idiosoma terminally with distinct bump-like projection bearing a pair of setae.

Gnathosoma . Hypostome as in Fig. 24 . Palptarsus with two-tined apotele, without paired macroeupathidial sensory setae. Chelicerae slender, with elongated proximal segment and bidentate movable digit ( Fig. 15 ); dentition of fixed digit and dorsal seta obscure. Tectum as in Fig. 20 .

Legs. Legs I–IV with well-developed pretarsi and claws. Chaetotaxy: femora I–IV: 2-5/4-2, 2-5/3-1, 1-3/ 1-1, 1-3/1-1; genua I–IV: 1-5/3-2, 2-5/2-2, 1-4/2-1, 1-4/1-1; tibiae I–IV: 1-5/3-2, 2-4/2-2, 1-3/2-1, 1-3/2-1. Tarsi II–IV with 18 setae. All leg setae short, most of the dorsal setae conspicuously thickened.

FIGURES 9–10. Halolaspis hypedon sp. nov., female. 9. Dorsal idiosoma; 10. Ventral idiosoma. Scale: 100 µm.

Etymology. The name of this new species is a combination of hypo - meaning under, and pedon, meaning earth, referring to the fact that the specimens were found in an underground chamber.

Notes. The species has erroneously been reported from Slovakia, under the name Iphidosoma pratensis , by Mašán (1994a). We compared the holotype of I. pratensis with the material published from Slovakia, and found that they are clearly not conspecific.

The monotypic genus Halolaspis may be distinguished from the other eviphidid genera by the following characters: (1) rectangular dorsal shield not covering whole dorsal surface, so the lateral and posterior dorsal cuticle is exposed; (2) dorsal shield setae j1 and J4 columnar, with widely rounded tips; (3) anterior dorsal shield fused with anterior ends of peritrematal shields, dorsal shield and peritrematal shields flanking deep strips of non-setose anterolateral cuticle; (4) vertex simple, without ventral armature, and bearing normal dorsally positioned setae j1 and z1; (5) coarse rugose-verrucose sculpture on dorsal shield, punctate-reticulate pattern on striated soft cuticle; (6) movable cheliceral digit bidentate; (7) endopodals II and sternal shield free, well separated; and (8) metasternal setae and pores situated on soft cuticle.

Biology. We consider this species to be edaphic, not a phoretic associate of a coprophilic insect, even though all of the three females examined were found separately in the subterranean brood chambers of the scarab beetle Copris lunaris . The scarab nests studied did not appear to provide optimal conditions for the reproduction and development of H. hypedon , since the mite was rare and sporadic in this microhabitat, and none of its immature stages were recorded. We provisionally place Halolaspis among the free-living genera of Eviphididae , without any close trophic or microhabitat relationship to C. lunaris .

Figures

FIGURES 11 – 24. Morphological structures in Eviphididae, females. 11. Halolaspis hypedon, sternal shield; 12. H. hypedon, sternal shield, different specimen; 13. Pseudoalliphis sculpturatus, chelicera, lateral view of distal segment; 14. P. sculpturatus, chelicera, ventral view; 15. H. hypedon, chelicera; 16. H. hypedon, peritrematal shield; 17. Alliphis halleri, tectum; 18. P. sculpturatus, tectum; 19. Alloseius pratensis, cheliceral digits, lateral view (after Karg, 1965); 20. H. hypedon, tectum; 21. A. pratensis, hypostome (after Karg, 1965); 22. A. halleri, hypostome; 23. P. sculpturatus, hypostome (after Karg, 1963); 24. H. hypedon, hypostome. Scale bars: 50 µm (Figs 11, 12, 15, 16 and 24) and 25 µm (Figs 13, 14, 17, 18 and 20). Figs 19 and 21 – 23 not to scale.