Monodontium sarawak, Raven, 2008

Raven, Robert J., 2008, A Revision Of The Mygalomorph Spider Genus Monodontium Kulczynski (Barychelidae: Araneae), Raffles Bulletin of Zoology 56 (1), pp. 29-44 : 41-44

Monodontium sarawak , new species

( Figs. 1 , 7A–D , 8A–E ; Tables 5, 6)

Material Examined. – East Malaysia: Sarawak: Lambir Hill National Park, 20km north of Miri, 4º14'N 114º02'E, 200 m, 17–18 Aug.2003, A. Schulz, Winkler Extraction, AS/03–6. MNHG, holotype male MNHN; allotype female, Matang area , via Kuching, 23 Nov.1977, T . E. Woodward , rainforest, litter, QM S72600 .

Diagnosis. – The male differs from that of M. bukittimah by the very incrassate third femur, and other species in the presence of rastellar spines and in the rectanguloid eye group and from M. mutabile in that PME are larger (relative to PLE) and the centres of the eyes of the back row form a recurved line whereas in M. mutabile the line is clearly procurved. The female, like the male, is unique in the incrassate femur 3.

Etymology. – A noun in apposition from the type locality.

Description. – Holotype, male (MNHN): Carapace 1.58 long, 1.20 wide. Abdomen 1.30 long, 0.80 wide. Total length, 3.3. Like M. bukittimah except:

Colour in alcohol: Carapace, chelicerae and legs fawn, not annulated; narrow post-foveal area brown. Abdomen dorsally purplish brown, laterally, ventrally and laterodorsally pallid.

Carapace: Pilosity: lightly setose but without hairs; striae indistinct, shallow, narrow. Bristles: 1–2 long erect black opposite fovea and beside posterior striae; ca. 20 posteriorly directed on caput; 3 long thick recurved; 5 or 6 short bristles on lateral margins anterior to fovea, 5–7 longer near posterior corners and 1 each posteriorly on posterior striae and 4 asymmetrically located behind fovea. Fovea short, slightly recurved, groove closed.

Eyes: Tubercle distinct. 3 rows. Back row procurved. Eye group occupies 0.42 of head-width 17:20:15. MOQ front width, back width, length, 9:13:8. AME: ALE: PME: PLE, 4:8:5:6.

Chelicerae: Rastellum of 3–5 long tapering spines. Furrow promargin with 6 teeth.

Labium: 0.24 wide, 0.06 long; cuspules absent.

Maxillae: 0.40 long in front, 0.54 long behind, 0.28 wide; with 5–8 blunt cuspules.

Sternum: 0.80 long and wide. Very small posterior sigilla evident in margin.

Legs: Tibia I predistally with slightly raised spur with stout curved megaspine, at base of spur slightly thick, blunt spine directed slightly prolateral of ventral; microspur small, triangular; upper megaspine stout, curved. Femur III strongly incrassate, medially 1.6 wider than basal width and 2 times wider than distal width.

Spines: Leg 1: fe d3w; pa 0; ti v2 distal + megaspines; me v1.2. Leg 2: fe d3w; pa 0; ti v1.1.3; me p2v1.3. Leg 3: fe d3r2; pa p2v1; ti p2d3r1v1.2.3; me p3r3v2.2.3. Leg 4: fe d3wr1; pa r1; ti p2r2v3.3.3; me p4r4v5.3. Palp: see Palp (below).

Claws: Three to five teeth in each of two rows (I–II), 2 rows of 2–3 on III, ectal row evident on IV. Tufts divided but narrow, weak, with few hairs on I, more numerous on III, IV.

Palp: Tibia with 13 short to long curved spines on retroventral tumesence beside embolus tip. Bulb relatively large quickly tapering to short slightly flanged embolus bent slightly at tip; cymbium bilobed, dorsal lobe broadly pointed; no tuft distally on cymbium. Cymbium short, with 2–4 long spine-like setae basally on dorsum giving the impression of spines.

Spinnerets: PMS absent. PLS 0.10 apart, 0.16 wide basally; length of basal, middle, apical, and total articles 0.20, 0.20, 0.04, 0.40, respectively.

Description: Allotype Female. QM S72600. Like male except as follows: Carapace 2.06 long, 1.47 wide. Abdomen 1.97 long, 1.31 wide. Total length, 4.63.

Colour in alcohol: Faded, partially translucent. Carapace light brown with slightly darker mottling. Abdomen dorsally brown, ventrally pallid.

Carapace: Pilosity: glabrous; 5 thick and 3 thinner anteromedial bristles; 2 thick and 4 smaller bristles between PME; 4 long between AME; 5–6 long bristles in posterior striae; few fine bristles on lateral margins. Fovea slightly procurved.

Eyes: Back row straight. Eye group occupies 0.44 of headwidth; front width, back width, length, 28:32:18. MOQ front width, back width, length, 17,23,10. AME:ALE:PME:PLE, 6:7:5:8. Eye interspaces: AME–AME, 0.5; AME–ALE, 1.2; ALE–PLE, 0.5; PME–PME, 2.5; ALE–ALE, 2.3.

Chelicerae: Rastellum of 2–4 long thick curved spines on inner edge and about 8 thinner but strong spines in transverse line laterally; only weak bristles above group on inner edge. Furrow promargin with 6 teeth, basomesally with group of about 15 fine teeth.

Labium: 0.19 long, 0.41 wide. Cuspules absent but 4 short pointed spinules in posterior half.

Maxillae: 0.59 long in front, 0.78 long behind, 0.47 wide; with 8–9 blunt cuspules.

Sternum: 1.00 long, 0.88 wide. No sigilla evident.

Legs: Femur III clearly the thickest; fringe of 6–8 strong bristles forming comb prodistally on femora III, IV and dorsally and laterally on patellae and tibiae III.

Palp: Claw tufts absent; dorsally with cluster of 10–15 short pointed bristles basodorsally. Few teeth on claw promargin.

Spines: Leg 1: fe d6w; pa 0; ti v3w; me v1.1.2. Leg 2: fe d5w; pa 0; ti v3w; me p1v1.1.2. Leg 3: fe (thick bristles)

THE RAFFLES BULLETIN OF ZOOLOGY 2008

d2r1; pa p2; ti p2d2r1v2; me p3r3v2.2.4. Leg 4: fe d3w; pa 0; ti weak bristles+v1; me p1r1v2.2.4. Palp: fe 0; pa 0; ti v2.2.3; ta r2v2.

Claws: There are ca. 6 teeth in each of two rows (I–II); III, IV long narrow, bare. Tufts weak.

Scopula: For length of metatarsus I but thin, divided widely; absent on II–IV. Tarsi: palp and I, thin, sparse; absent on II– IV.

Spinnerets: PMS absent. PLS length of basal, middle, apical, and total articles 0.40, 0.09, 0.03, 0.50, respectively.

Spermathecae: A single broad lobe with smaller anterior lobe joined by narrow neck.

Distribution. – Known only from tropical rainforest in Sarawak, East Malaysia.

Remarks. – Two females from Sarawak in the same collection are not adult but have teeth on promargin of palpal claw, no tufts on palp, and no sign of teeth on legs 3 and 4 but 2 rows on legs I and 2.

Other material examined. – 1 juv., Nabire [3º23'S 135º31'E], New Guinea, 5 Sep.1962, H. Holkmann, ( BPBH) ; 1 juv.,

Finisterre Mts , Nakok Valley, Budemu, [5º54'S 146º06'E], 4,150 ft (ca. 1,265 m), M.E. Bacchus coll. no 51, 15–25 Oct.1964, BMNH & Newcastle-upon-Tyne Expedition (BMNH).

Figures

Fig. 1. Occurrence of Monodontium.

Fig. 7. Monodontium sarawak, new species, holotype male: A, carapace, abdomen, femora, dorsal view showing incrassate femur III, inset, eyes; B, sternum, maxillae, labium and chelicerae; C, palp, bulb (inset), retrolateral view; D, tibia and metatarsus I, prolateral view. Scale bar = 1 mm.

Fig. 8. Monodontium sarawak, new species, allotype female: A, habitus. B, spermathecae; C, carapace, dorsal view; D, eyes; E, sternum, maxillae, labium and chelicerae with rastellum. Scale bars = 1 mm, except B, D = 0.10 mm.