Oedignatha platnicki, Song et Zhu, 1998

Chen, Shyh-Hwan & Huang, Wen-Juen, 2009, A Newly Recorded Spider Oedignatha platnicki Song et Zhu 1998 from Taiwan, with Description of the Female (Araneae, Corinnidae), BioFormosa 44 (1), pp. 31-36 : 32-34

Oedignatha platnicki Song et Zhu 1998 ( Figs. 1-9 )

Oedignatha platnicki Song and Zhu, 1998: 105 , f. 2 A-F; Song, Zhu and Chen, 1999: 429, f. 255M-N.

Specimens examined. TAIPEI CITY, Wenshan District, Mt. Toad , alt. 100 m, collected by pitfall traps: 5♂♂, NTNUB - Ar 27081-27085 , 29 July 2004 ; 1♂, NTNUB - Ar 27086 , 4 Aug. 2004 ; 2♂♂, NTNUB - Ar 27090, 27091 , 19 Aug. 2004 ; 1♀, NTNUB - Ar 31919 , 7 May 2007 ; 1♂, NTNUB - Ar 41000 , 22 June 2007 ; 1♀, NTNUB - Ar 41003 , 25 June 2007 ; 4♂♂, 2♀♀, NTNUB - Ar 41262-41265, 41274, 41275 , 26 Oct. 2007 ; 1♀, NTNUB - Ar 41290 , 2 Sept. 2007 ; 2♂♂, 4♀♀, NTNUB - Ar 41322, 41324-41328 , 16 Sept. 2007. All specimens were collected by Shyh-Hwang Chen .

Diagnosis. Oedignatha platnicki differs from O. scrobiculata (characters in parentheses) by the relatively smooth carapace (pitted configuration) and without any paired light spots on the abdomen (with 4 pairs of light spots). The shape of tibial apophyses and structures of palpal organs in male palps, and structures of female genital organs are also diagnosed. Of the other congeners, O. platnicki most resembles O. spadix from eastern Indonesia, but differs from the latter (characters in parentheses) by the male having two minute teeth on the dorsal branch of tibial apophysis (without any minute tooth), and the female having the mushroom-shaped vulva and without the crescent ridge on the epigyne (not mushroom-shaped and present the crescent ridge).

Description. Female (NTNUB-Ar 41322). Total length 6.77; carapace length 2.92, width 2.15; abdomen length 3.85, width 2.46. Measurements of palp and legs: palp 3.54 (1.23, 0.46, 0.77, 1.08); leg I 10.38 (2.69, 3.69, 2.46, 1.54), II 8.16 (2.31, 2.62, 1.92, 1.31), III 7.24 (1.93, 2.23, 1.85, 1.23), IV 10.54 (2.62, 3.31, 2.92, 1.69). Diameters of eyes in ratio, AME: ALE: PME: PLE = 0.17: 0.18: 0.12: 0.12.

Carapace ( Fig. 1 ) reddish brown, smooth and well sclerotized, with a black, longitudinal thoracic groove and dark brown cervical grooves, radial grooves and margin of carapace; clypeus with a conical hump in front of AMEs. AER straight and PER slightly procurved when viewed dorsally. PER longer than AER. ALE> AME> PLE = PME. Distance between AMEs (0.12) longer than that of AME and ALE (0.05), distance between PMEs (0.23) slightly longer than that of PME and PLE (0.22). MOA

length 0.22, anterior width 0.43, posterior width 0.45. Height of clypeus 1.4 times diameter of AME. Chelicerae ( Figs. 1, 2 ) stout, dark brown, geniculate anteriorly, promargin of fang groove armed with 3 robust triangular teeth and retromargin with 7 smaller teeth; fang dark brown. Endite ( Fig. 3 ) brown, longer than width and narrower in the middle. Labium dark brown, hour-glass in shape, longer than width. Sternum heart-shaped, margin concaved at the base of coxa and intruding posteriorly to between coxae IV, and connected with carapace by sclerotized stripes between coxae. Legs formula 4-1-2-3. Leg spination: tibiae I with 10 anterior and 8 posterior ventral spines, II with 9 and 7, III with 2 and 2, and IV with 3 and 2 respectively; metatarsi I with 7 anterior and 6 posterior ventral spines, II with 6 and 5 ventral spines respectively, III and IV each with 2 ventral spines on anterior and posterior margins. Opisthosoma ( Figs. 1, 3 ) ovoid, grayish brown, without any paired white markings; dorsum with a brown, oval scutum covered two fifth of abdominal length, and ventral with a well developed epigastric scutum and a pair of narrow postgenital scuta. Epigynum ( Figs. 4, 5 ) with copulatory openings adjacent to anterior border of epigastric fold. Vulva heavily sclerotized, with short copulatory ducts and two pairs of sperm storage sacs: a larger, relatively thin-walled bursa anteriorily and a smaller, thick-walled spermatheca posteriorily.

Male (NTNUB-Ar 27086). Similar to female in shape and coloration. Total length 6.54; carapace length 3.23, width 2.31; abdomen length 3.31, width 2.00. Measurements of palp and legs: palp 3.77 (1.38, 0.54, 0.62, 1.23); leg I 10.94 (2.85, 3.85, 2.62, 1.62), II 8.91 (2.46, 2.92, 2.15, 1.38), III 7.61 (2.00, 2.38, 2.00, 1.23), IV 10.84 (2.77, 3.38, 2.92, 1.77). Diameters of eyes in ratio, AME: ALE: PME: PLE = 0.19: 0.15: 0.12: 0.13.

AER straight and PER slightly procurved when viewed dorsally. PER slightly longer than AER. AME> ALE> PLE> PME. MOA length 0.4, anterior width 0.44, posterior width 0.49. Height of clypeus 2 times diameter of AME. A prominent, conical process situated in front of distal end of chelicerae. Promargin of fang groove armed with 3 robust triangular teeth and retromargin with 7 (left) or 8 (right) smaller teeth. Legs formula 1-4-2-3. Leg spination: tibiae I with 9 ventral spines on anterior and posterior margins, II with 8 anterior and 7 posterior ventral spines, III and IV each with 2 ventral spines on anterior and posterior margins; metatarsi I with 7 and 6, II with 6 and 5 anterior and posterior ventral spines respectively, III and IV each with 2 ventral spines on anterior and posterior margins. Opisthosoma ( Figs. 6, 7 ) having a brown dorsal scutum covered nearly all abdominal length, and having well developed epigastric and postgenital scuta ventrally that covered two third of abdominal length. A semi-circular scutum in front of spinnerets.

Palpal tibia ( Figs. 8, 9 ) with two distal apophyses, a pointed fingerlike ventral apophysis and a two-toothed claw-like retrolateral one. Conductor well sclerotized; a narrow membranous tegular apophysis aligned with conductor; thread-like embolus longer, arising retrolaterally and curving in a 3-quatore circle around tegulum, clockwise in left palp.

Variations. Five females and six males were measured. Variations among females are followed by those of males (with the mean in parentheses). Total length 5.77-6.77 (6.17) and 5.08-6.54 (5.76); carapace length 2.54 -3.00 (2.77) and 2.46-3.23 (2.84), width 1.85-2.15 (2.03) and 1.77-2.31 (2.00); abdomen length 3.08-3.85 (3.40) and 2.62-3.31 (2.93), width 1.69-2.46 (2.15) and 1.62-2.00 (1.75). Promargin of fang groove armed with 3 robust teeth, and retromargin varying with 6-8 in both sexes. Ventral spines on left legs in five females counted: tibiae I with 9-10 (mostly 10, in 60%) on anterior margin and 8-9 (mostly 9, in 60%) on posterior margin, II with 8-9 (mostly 9, in 80%) and 6-7 (mostly 7, in 80%), III with 2 and 2, and IV with 2-3 (mostly 3, in 80%) and 2 respectively, and metatarsi I with 6-7 (mostly 7, in 60%) and 6, IIwith 6 and 5, III with 2 and 2, and IV with 2-3 (mostly 2, in 80%) and 2 respectively. Ventral spines on left legs in six males counted: tibiae I with 9 on anterior margin and 8-9 (mostly 8, in 83%) on posterior margin, II with 7-9 (mostly 8, in 67%) and 5-9 (mostly 7, in 50%), III with 2-4 (mostly 2, in 67%) and 2-4 (mostly 2, in 67%), and IV with 3-5 (mostly 3, 67%) and 2-3 (mostly 2, 67%) respectively, and metatarsi I with 6-7 (mostly 6, 67%) and 6, II with 6 and 4-5 (mostly 5, 83%), III with 2-3 (mostly 2, in 83%) and 1-2 (mostly 2, in 83%), and IV with 2-3 (mostly 2, in 83%) and 2-3 (mostly 2, in 83%) respectively.

Distribution. Hong Kong and Taiwan.

Discussion

Genus Oedignatha currently contains 36 species world-wide ( Platnick, 2009), of which only O. platnicki and O. scrobiculata (= Phrurolithus ulopatulisus Barrion et Litsinger 1995 ) have been recorded from Hong Kong and the Philippines, respectively, neighboring the main island of Taiwan ( Song and Zhu, 1998, Deeleman-Reinhold, 2001). In this paper, we confirm the presence of both species in Taiwan. Their distribution may be allopatric in the main island of Taiwan. Up to the present, Oedignatha platnicki is known only from northern Taiwan, i.e., Taipei City (Mt. Toad) and Taipei County (Mt. Kuanyin, Chen unpublished data), while O. scrobiculata is from southern Taiwan, Kengting, Pingtung County ( Tso et al., 2005) and from eastern Taiwan, Lichia, Taitung County (Chen unpublished data), about 100 km north to the Kengting National Park. However, our inference is based on insufficient data. Further investigation is needed.

Oedignatha scrobiculata shows remarkably sexual dimorphism ( Deeleman-Reinhold, 2001). Our study indicates that O. platnicki also shows conspicuous sexual dimorphism. Heavily sclerotized scuta of the opithosoma, including a dorsal scutum, a ventral epigastric scutum and a pair of postgenital scuta, are much well developed in male than in female in O. platnicki . Leg I is the longest leg in male, while leg IV is the longest one in female. All these features are the same as those in O. scrobiculata .

Figures

Figure 1 – 5. Oedignatha platnicki Song & Zhu 1998, female (NTNUB-Ar 41322). 1. dorsal side of body; 2. lateral side of body; 3. ventral side of body; 4. epigynum, ventral view; 5. vulva, dorsal view. Scales: 1 mm (1 - 3) and 0.5 mm (4, 5)

Figure 6 – 9. Oedignatha platnicki Song & Zhu 1998, male (NTNUB-Ar 27086). 6. dorsal side of body; 7. ventral side of body; 8. left male palp, ventral view; 9. left male palp, prolateral view. Scales: 1 mm (6, 7) and 0.5 mm (8, 9).