A new genus of oonopid spiders from Myanmar (Araneae, Oonopidae)

Abstract A new genus, Kachinia Tong & Li, gen. n., including two new species, K.putao Tong & Li, sp. n., and K.mahmolae Tong & Li, sp. n., is described from Myanmar. The new genus belonging to the subfamily Oonopinae Simon, 1890, currently is the only member of the Brignolia-Opopaea clade with leg spines.


Introduction
The taxonomy of the family Oonopidae Simon, 1890 has a huge progressed in the last decade, more than 1,300 new species, and 50 new genera were described in the past ten years. This spider family currently includes 1,801 extant described species in 114 genera (WSC 2018), making it the 8 th most speciose spider family so far following the hyperdiverse spider groups such as jumping spiders (Salticidae Blackwall, 1841). The Oonopidae were traditionally divided into two informal groups, the "loricati", harboring oonopids with heavily sclerotized bodies, and the "molles", which includes the remaining, soft-bodied goblin spiders (Simon 1893). This fundamental dichotomy was later fixed as formal categories at subfamily level, Gamasomorphinae Petrunkevitch, 1923 for the "loricati" and Oonopinae Simon, 1890 for the "molles" (Petrunkevitch 1923). Platnick et al. (2012a) clarified the classification of the oonopids. Three subfamilies were recognized, i.e., Oonopinae, Orchestininae Chamberlin andIvie, 1942, andSulsulinae Platnick, 2012. The subfamily Oonopinae harbor the bulk of oonopid genera, including those groups formerly regarded as belonging to ''Gamasomorphinae''. However, the task of recognizing homologous instances of modification on the body sclerotization will play a central role in future efforts to detail the classification of the higher Oonopinae (Bonaldo et al. 2014).
The oonopid spiders of Myanmar have been poorly studied. Hitherto, only four extant species, Gamasomorpha bipeltis Thorell, 1895, G. inclusa Thorell, 1887, G. psyllodes Thorell, 1897and G. sculptilis Thorell, 1897, have been recorded from Myanmar (WSC 2018). The present paper expands the known oonopid diversity of Myanmar by adding a new genus and two new species.

Materials and methods
The specimens were examined using a Leica M205C stereomicroscope. Details were studied under an Olympus BX51 compound microscope. Photos were made with a Canon EOS 550D zoom digital camera (18 megapixels) mounted on an Olympus BX51 compound microscope. Vulvae were cleared in lactic acid. Scanning electron microscope images (SEM) were taken under high vacuum with a Hitachi S-4800 after critical point drying and gold-palladium coating. All measurements were taken using an Olympus BX51 compound microscope and are in millimeters.
References to figures in the cited papers are listed in lowercase (figure or figs); figures from this paper are noted with an initial capital (Figure or Figs Etymology. The generic name is derived from the type locality, 'Kachin', and is feminine in gender. Diagnosis. Kachinia gen. n. resembles Brignolia Dumitrescu & Georgescu, 1983, the member of Brignolia-Opopaea clade (De Busschere et al. 2014), by the heavily sclerotized and darkened palps of males, and the endogyne bearing a T-shaped anterior sclerite and tube-like posterior receptacle, but can be easily distinguished by the presence of anterior leg spines in both sexes, the deeply incised labium and the branched endites in males and the absence of external features of endogyne (B. parumpunctata (Simon, 1893) with external modifications, see Platnick et al. 2011: figure 69). The new genus is also similar to Ischnothyreus Simon, 1893, but can be separated by the deeply incised labium, the branched endites, the unmodified chelicerae and the totally fused cymbium and bulb in males (Ischnothyreus peltifer (Simon, 1892), and most species of this genus usually with a tooth-like projection on the anteromedian tip of the endites, with processes on the base of the cheliceral fang and cymbium fused with bulb but with clearly defined seam, see Kranz-Baltensperger 2011: figure  Description. Male. Body yellow-brown, legs yellow. Carapace (Figs 1A, E, 4A, E): broadly oval in dorsal view, with brown egg-shaped patches behind eyes, eyes rather low; pars cephalica strongly elevated, pars thoracica higher than pars cephalica, with rounded posterolateral corners, poste rolateral edge without pits, posterior margin not bulging below posterior rim, antero lateral corners without extension or projections, posterolateral surface without spikes, surface of pars cephalica smooth, thorax without depressions, fovea absent, without radiating rows of pits; lateral margin straight, smooth, rebordered, with small blunt denticles; marginal setae present. Eyes (Figs 1B, H, 4B, H): six, well developed, arranged in a compact group; ALE largest, PME, PLE subequal; ALE-PLE separated by less than ALE radius, PME touching each other; posterior row recurved from above, procurved from front. Clypeus (Figs 1F, H, 4F, H): margin un modified, sinuous in front view, vertical in lateral view, median projection absent; light se tae, needlelike. Chilum absent. Mouthparts (Figs 1G, 2E, 5E): chelicerae straight; labium rectangular, anterior margin deeply incised (ldi), same as sternum in sclerotization, not fused to sternum; endites slender, anterior margin with a row of small serrula, distally branched, with dense, patch of short feather-like setae (fls) on inner branch (ibr) and two long setae (lse) on outer branch (obr). Sternum (Figs 1C,D,4C,D): longer than wide, with radial furrows between coxae, uniform, not fused to carapace, median concavity absent, surface smooth, anterior margin unmodified, posterior margin not extending posteriorly of coxae IV, anterior corner unmodified, distance between coxae approximately equal, lateral margins unmodified, without posterior hump; setae sparse, dark, needlelike, evenly scattered, without hair tufts. Abdomen (Figs 1C, E, 4C, E): ovoid, rounded posteriorly. Dorsal scutum covering entire dorsum, strongly sclerotized, without pattern. Epigastric scutum strongly sclerotized, surrounding pedicel. Postgastric scutum strongly sclerotized, long, almost rectangular, covering nearly the full length of the abdomen, anterior mar gin unmodified, with posteriorly directed lateral apodemes. Book lung covers large, smooth, anterolateral edge unmodified. Scutopedicel region has short tube, scutum not extending far beyond dorsum of pedicel, plumose hairs absent. Anterior spiracles connected ( Figure 1C) or not ( Figure 4G   flat, wide and elongated lobe of the embolus complex (clo, Figure 2B, D) and the absence of long, strong setae on the abdominal scutum in males, and the presence of a crescent-shaped plate (pl, Figure 3G, I) of the endogyne.
Genitalia. Ventral view ( Figure 3I): middle part of anterior margin of postgastric scutum strongly sclerotized (asr), with a narrow, crescent-shaped plate (pl). Dorsal view ( Figure 3J): with a T-shaped sclerite (tsc) anteriorly, followed posteriorly by a tube-like posterior receptacle (pr); from lateral view, the tube curved ventrally, then extends anteriorly, ending at the crescent-shaped plate, the ending point nearly reaching anterior margin of postgastric scutum ( Figure 3G, H, I); a very thin, long and line-like structure (lst) can be seen inside the tube.
Distribution. Myanmar (Kachin State).  (Figure 4I), the collapsed lobe of the embolus complex (clo, Figure 5B, D) and the long, strong setae on the abdominal scutum (sls, Figure 4E, G) in males, and the presence of a triangular plate (pl, Figure 6G, I) of the endogyne.
Female. Habitus as in Figure 6A, C, E. Body length 1.72; carapace 0.75 long, 0.64 wide; abdomen 0.91 long, 0.67 wide. Postgastric scutum 0.34 long, 0.45 width, length/width ratio = 0.75. Genitalia. Ventral view ( Figure 6G, I): middle part of anterior margin of postgastric scutum strongly sclerotized (asr), with a triangular plate (pl). Dorsal view ( Figure 6J): with a T-shaped sclerite (tsc) anteriorly, followed posteriorly by a tube-like posterior receptacle (pr) ( Figure 6I); from lateral view, the receptacle curves ventrally, then extends anteriorly, ending at the triangular plate, the ending point far away the anterior margin of postgastric scutum ( Figure 6G, H, I); a very thin, long and line-like structure (lst) can be seen inside the tube.