Molotra milloti, Ubick & Griswold, 2011

Ubick, Darrell & Griswold, Charles E., 2011, The Malagasy Goblin Spiders of the New Genus Molotra (Araneae: Oonopidae), American Museum Novitates 2011 (3729), pp. 1-72 : 21-68

Molotra milloti species group

DIAGNOSIS: The single specimen representing this group is a male which differs from all other Molotra species in somatic characters, including its slightly larger size (2.4 mm), carapace and abdomen with thick erect setae (figs. 293–300), book lung covers reduced to narrow scars (fig. 297), legs armed with numerous bristles, some spinelike (figs. 307–310, 317, 318), and tarsal claws heterodentate (figs. 319–326). The embolar region has dorsal and ventral lobes closely contiguous (seemingly fused) and forming a sinuous interface (figs. 6, 327–341), unlike other Molotra where lobes are at least somewhat free and their interface straight (figs. 1–5).

SPECIES INCLUDED: Molotra milloti .

Molotra milloti , new species

Figures 6 , 293–341 ; map 1; table 1

TYPES: Male holotype from Madagascar, Mahajanga, Reg. du Sambirano ( Ankify ) [= Dauphin Bleu, 13.53500°S, 48.37313°E] (Sep 1946, J. Millot), deposited in MNHN (PBI_OON_35300).

ETYMOLOGY: It is a pleasure to name this species after J. Millot, collector of the holotype and the first arachnologist to report on Malagasy oonopids.

DIAGNOSIS: Same as for species group.

MALE (PBI_OON_35300): Total length 2.40. CEPHALOTHORAX: Carapace with surface of elevated portion of pars cephalica granulate, sides granulate (fig. 305); nonmarginal pars cephalica setae light, long and stout (figs. 304–306). Sternum wider than long, surface finely reticulate (pitted), anterior margin with moderate transverse excavation, setae abundant, densest laterally on mounds between the furrows (fig. 303). Mouthparts: endites distally excavated. ABDOMEN: Book lung covers small, very narrow (fig. 297). Posterior and anterior spiracles connected by grooves (fig. 301). Pedicel with scutopedicel region unmodified, without ridges (fig. 298). Dorsal scutum surface granulate. Epigastric scutum dorsal extension more than two times pedicel diameter (figs. 295, 305). Postepigastric scutum with posteriorly directed lateral apodemes, prominent in ventral view, extend beyond posterior tracheal groove, external openings evident (fig. 301). Dorsal setae present, light, stout, long and erect. LEGS: Yellow-brown, patella plus tibia I shorter than carapace. Legs with numerous erect bristles, few spinelike: tibiae I, II v0-1p-0 and tibia IV v0-0-1p (figs. 307–310, 317, 318). Tarsal claws: superior claw surfaces striate; proclaws and retroclaws with dissimilar dentition; tarsus I proclaw with three lateral (broad, basal) and four to five median (apical, thinner) teeth, retroclaw with three broad median teeth, laterals absent; tarsus III proclaw with three lateral (broad) and five median (short, apical) teeth, retroclaw with three broad median teeth, laterals absent; tarsus IV proclaw with three lateral (broad) and five median (short, apical) teeth, retroclaw with five large median teeth, laterals absent (figs. 319–326). GENITALIA: Epigastric region with sperm pore small, situated anteriad of anterior spiracles; prominent groove present, connecting anterior respiratory spiracles and apodeme openings (fig. 301). Palp femur attaches to patella subbasally (figs. 327–330), tibia larger than patella; embolar region wrinkled dorsally (fig. 339), dorsal lobe large, with prolateral carina, ventral lobe wrinkled basally (fig. 340).

FEMALE: Unknown.

NOTES: The generic placement of this species is tentative because of its striking somatic differences from other Molotra . The discovery and study of the female will be essential for resolving this problem.

The legs of this species are densely covered in bristles, a few of which are spinelike. The prolateral bristle on tibia IV is slightly thicker than the surrounding bristles, although it is also shorter than most (fig. 309). Also, the prolateral bristle on tibia I, although no thicker than the rest, has a larger and notched socket (fig. 318). This spinelike bristle is positioned in a paired ventral series, similar to that of spines in other Molotra (and many other oonopids), suggesting homology between both types of bristles and typical leg spines.

OTHER MATERIAL EXAMINED: None.

DISTRIBUTION: Known only from the type locality.

Figures

FIGS. 1–6. Molotra species, embolar region of male palpi, prolateral view. 1. M. molotra. 2. M. katarinae. 3. M. ninae. 4. M. suzannae. 5. M. tsingy. 6. M. milloti. Colors show homologous parts: yellow embolus, green dorsal lobe, red ventral lobe. The tentative homologies of the M. tsingy palp are shown as dashed lines and the unhomologized dorsal prong is shown in white dash.

FIGS. 293–301. Molotra milloti, new species, male (PBI_35300). 293. Habitus, ventral view. 294. Same, dorsal view. 295. Same, lateral view. 296. Abdomen, ventral view. 297. Same, sublateral view, with arrows showing reduced book lung cover. 298. Same, anterior view. 299. Same, posterior view. 300. Same, lateral view, with arrow showing anterior overhang of abdomen. 301. Epigastric region, ventral view, with arrow to sperm pore and dash to posterior apodeme visible through cuticle. Scale bars (horizontal): 200 µm.

FIGS. 302–310. Molotra milloti, new species, male (PBI_35300). 302. Cephalothorax, dorsal view. 303. Same, ventral view. 304. Same, anterior view. 305. Same, lateral view. 306. Same, posterior view. 307. Leg I, prolateral view. 308. Same, retrolateral view. 309. Leg IV, prolateral view, with arrow showing spinelike bristle. 310. Same, retrolateral view. Scale bars: 200 µm.

FIGS. 311–318. Molotra milloti, new species, male (PBI_35300). 311. Tarsal organ of palp, dorsal view. 312. Same, tarsus I. 313. Same, tarsus III. 314. Same, tarsus IV. 315. Trichobothrium of metatarsus I, dorsal view. 316. Same, tibia I. 317. Leg I, dorsolateral view. 318. Tibia I, subventral view, with arrow showing spinelike socket. Scale bars: 100 µm (317, 318), 10 µm (311–316).

FIGS. 319–326. Molotra milloti, new species, male claws (PBI_35300). 319. Tarsal claws I, dorsal view. 320. Same, dorsal view. 321. Same, anterior view. 322. Same, retrolateral view. 323. Tarsal claws III, retrolateral view. 324. Same, ventral view. 325. Tarsal claws IV, anterior view. 326. Same, subventral view. L = lateral (outer) teeth of tarsal claw, M = median (inner) teeth, PC = proclaw, RC = retroclaw. Scale bars: 10 µm.

FIGS. 327–333. Molotra milloti, new species, male palp (PBI_35300). 327. Prolateral view. 328. Retrolateral view. 329. Prolateral view, methyl salicylate preparation. 330. Apical view. 331. Dorsal view. 332. Ventral view. 333. Same, different angle. Arrows point to proximal junction of the embolar lobes. DL = dorsal lobe. Scale bars: 200 µm.

FIGS. 334–341. Molotra milloti, new species, male palp. (PBI_35300). 334. Palp, prolateral view. 335. Same, retrolateral view. 336. Same, dorsal view. 337. Embolar region, dorsal view. 338. Same, prolateral view. 339. Same, dorsolateral view. 340. Same, ventral view. 341. Magnified view of embolar tip. DL = dorsal lobe, O = embolar opening, VL = ventral lobe. Scale bars: 100 µm (334–336), 50 µm (337, 338, 340), 20 µm (339), 10 µm (341).