Singaporemma singulare Shear, 1978

Lin, Yucheng, Koh, Joseph K. H., Koponen, Seppo & Li, Shuqiang, 2017, Taxonomic notes on the armored spiders of the families Pacullidae and Tetrablemmidae (Arachnida, Araneae) from Singapore, ZooKeys 661, pp. 15-60 : 26-27

Singaporemma singulare Shear, 1978 Figs 22, 23 A–E, G–H, 24, 25, 26

Singaporemma singularis Shear, 1978: 36, figs 108-111; Lehtinen, 1981: 31.

Examined materiral.

Holotype ♂ and paratype 1♀ (AMNH), SINGAPORE: near MacRitchie Reservoir, 25 October 1950, M.W.F. Tweedie leg.

Other material.

10♂ and 6♀ (LKCNHM), SINGAPORE: Central Catchment Nature Reserve, treetop walk, 1°21'13.3"N, 103°48'29.4"E, 28 August 2015, S. Li and Y. Tong leg; 5♂ and 4♀ (NHMSU), SINGAPORE: Central Catchment Nature Reserve, Treetop Walk, 1°21'13.3"N, 103°48'29.4"E, 28 August 2015, S. Li and Y. Tong leg.

Other species studied for comparison.

Singaporemma adjacens Lehtinen, 1981 (Fig. 23F; Lehtinen, 1981: 31, figs 47, 51, 64). Holotype ♂ (NHMSU), VIETNAM: Quang Ninh, Ha Long, in litter of dense jungle close to seashore, altitude 10 m, 12 October 1978, P.T. Lehtinen leg.

Diagnosis.

Singaporemma singulare is distinguished from Singaporemma bifurcata (see Lin and Li, 2010: 26, figs 35-37) and Singaporemma wulongensis (see Lin and Li, 2014: 46, fig. 8 A–F) by the embolus without any furcate end; from Singaporemma adjacens (see Fig. 23F and Lehtinen, 1981: 31: fig. 64 a–b) by the narrower embolus. It is similar to Singaporemma banxiaoensis (see Lin and Li 2014: 42, fig. 5 A–D), Singaporemma halongense (see Figs 19A, 21 C–D and Lehtinen, 1981: 31, fig. 62 a–b), and Singaporemma lenachanae sp. n. (Figs 17 A–E, 18 A–F, 19 B–I) in having a straight embolus with modified end, but the male can be distinguished by the initial position of embolus (Figs 23A, 25D) and the knife-shaped embolic end (Figs 23D, 25C). Female distinguished by the absence of central process (Fig. 26C) and the punctured rather than reticulated clypeal area (Fig. 24F).

Description.

Male. Coloration: body reddish-brown; legs yellowish-brown.

Measurements: total length 1.14; carapace 0.50 long, 0.45 wide, 0.44 high; abdomen 0.73 long, 0.60 wide, 0.52 high; clypeus 0.19 high; sternum 0.30 long, 0.33 wide. Length of legs: I 1.24 (0.40, 0.13, 0.30, 0.19, 0.22); II 1.10 (0.34, 0.12, 0.26, 0.18, 0.20); III 0.99 (0.30, 0.12, 0.22, 0.17, 0.18); IV 1.36 (0.43, 0.14, 0.34, 0.23, 0.22).

Prosoma (Fig. 24 A–B, E, G): carapace finely reticulated, except for the radial grooves in thoracic area, marginally denticulate (Fig. 24A, E); eyes with black base, ALE>AME>PLE, ALE and PLE adjacent, ARE straight; cephalic part raised, top flat, covered with long setae (Fig. 24G); clypeus high, sharply sloping forward, bears densely short setae, anterior margin rugose (Fig. 24E); Cheliceral frontal surface sculptured, but lack of process, cheliceral lamina developed; sternum finely reticulated, marginally rugose, and posteriorly truncated. Legs striated, cuticle scalelike.

Opisthosoma (Figs 24 A–B, G; 26A): covered with serrated setae; dorsal scutum oval, reticulated, bears sparse nodules and setae; ventral scutum reticulated, margin rugose; booklung cover rounded, smooth; lateral scutum I long, exceeding by far the posterior margin of preanal scutum; perigenital scutum large; postgenital scutum wide, its posterior margin overlaps joint of anterior margin of preanal scutum; preanal scutum rectangular, with blunt corners.

Palp (Figs 23 A–E; 25 A–E): femoral cuticle granular, striated, approximately 2.6 times as long as patella; patella short; tibia swollen, 1.8 times as wide as femur; cymbium wide and compressed; bulb long egg-shaped, surface smooth; spermatic duct basally wide, and tapering to the base of embolus after coiling a loop; embolus thin and long, weakly sclerotized, starting from the prolateral pericenter of bulbous surface, and almost straight downwards (Figs 23A, 25D); embolic end flexuous, knife-shaped (Figs 23D, 25C).

Female. Coloration: body slightly lighter than in male; legs yellowish-brown.

Measurement: total length 1.18; carapace 0.50 long, 0.44 wide, 0.44 high; abdomen 0.74 long, 0.63 wide, 0.56 high; clypeus 0.17 high; sternum 0.29 long, 0.32 wide. Length of legs: I 1.24 (0.40, 0.14, 0.28, 0.20, 0.22); II 1.14 (0.37, 0.13, 0.25, 0.19, 0.20); III 1.04 (0.32, 0.12, 0.22, 0.18, 0.20); IV 1.39 (0.44, 0.13, 0.35, 0.24, 0.23).

Prosoma (Fig. 24 C–D, F, H) as in male, except for clypeal area no reticulated, but covered with short setae. Palp reduced. Legs also as in male.

Opisthosoma (Figs 24 C–D, H; 26A): dorsal and ventral scuta as in male; lateral scutum I long, exceeding by far posterior margin of preanal scutum; perigenital scutum large, long oval; postgenital scutum slightly curved, faintly wider than preanal scutum, overlapped joint the anterior margin of preanal scutum; preanal scutum smooth, nearly rectangular, with sparse serrated setae.

Genitalia (Figs 23H, 26 B–D): epigynal pit small, indistinct (Fig. 26B, D), closed to vulval posterior margin (Fig. 21C); vulval stem wide, connected with lateral horns; central process absent; inner vulval plate “T” -shaped, basally sclerotized (Fig. 26C); lateral horn narrow, and straight; vulval ducts relatively wide, upward curved, translucent, connected to the saccular seminal receptaculum (Fig. 26C).

Distribution.

Singapore.

Remarks.

This species is originally described from Singapore and was designated as the type species of the genus Singaporemma by Shear (1978). Based on the only male specimen available at that time, he had illustrated an embolus of the right palp that was said to be "curving sharply posteriorly" (Shear, 1978: 36, figs 109-110), i.e. bent at right angles at about mid-length. Schwendinger and Košulič (2015) suggested that Shear’s description of Singaporemma singulare was based on an atypical specimen. They noted that five other Singaporemma male specimens from Singapore, one of them from the type locality itself, all had "essentially straight emboli (only slightly bent ventrad) on both palps". We have since reexamined the holotype of the species and photographed its left palp (Fig. 23 A–E). We can now confirm that Shear (1978) had indeed described a deformed embolus.