Nasoona eustylis ( Simon, 1909 )

Tu, Lihong & Li, Shuqiang, 2004, A Preliminary Study Of Erigonine Spiders (Linyphiidae: Erigoninae) From Vietnam, Raffles Bulletin of Zoology 52 (2), pp. 419-433 : 426-428

Nasoona eustylis ( Simon, 1909)

( Figs. 6 , 7 )

Trematocephalus eustylis Simon, 1909: 98 , Figs. 1 , 2 . (New combination)

Trematocephalus bivittatus Simon, 1909: 98 . (New synonymy)

Material examined. – 1 male ( MNHNP AR 11924 ), type of Trematocephalus eustylis Simon, 1909 , collected from Luc-Nam

(Blaise); 1 female ( MNHNP AR 11928 ), type of Trematocephalus bivittatus Simon, 1909 , collected from Song-Luc-Nam (Blaise) ; 3 males, 2 females, Viet Lann Village , Ha Jiang Province, Vietnam (042), 10 Dec.2000 ; 1 male, 2 females, Viet Lann Village , Ha Jiang Province, Vietnam (036), 10 Dec.2000 ; 2 males, Viet Lann Village , Ha Jiang Province, Vietnam (027), 10 Dec.2000 . 1 female, Viet Lann Village , Ha Jiang Province, Vietnam (025), 10 Dec.2000 ; 3 females, Sac Ha Village , Cao Bang Province, Vietnam (072), 17 Dec.2000 ; 1 male, Sac Ha Village , Cao Bang Province, Vietnam (063), 17 Dec.2000 ; 1 male, Son Tay Province, Bavi District , Vietnam (113), 23 Dec.2000 .

Diagnosis. – The male is easily recognized by its cephalic lobe, bearing a prominent forward-directed spine with a hooked tip at top and bending bristles behind ( Fig. 6A ). The female is diagnosed by the bird mouth-like epigynum in lateral view ( Fig.7D ).

Description of male. – Total length: 2.00. Carapace: 0.88 long, 0.65wide. Abdomen: 1.20 long, 0.70 wide. Carapace ( Fig. 6A ) brown with black margin, cephalic portion elevated behind ocular area, bearing a prominent forward-directed spine with hooked tip at top, and several bending bristles behind. Clypeus straight. Eyes subequal, with black surroundings; AER recurved, AME-AME equal to AMEd; AME-ALE shorter; PER straight, posterior eyes separated by about PMEd; ALE and PLE juxtaposed. Chelicerae brown as carapace, fang groove with six promarginal and four retromarginal teeth ( Fig. 6B ). Sternum darker than carapace. Abdomen dark gray, without pattern. Lengths of legs: I 3.15 (0.90+ 1.00+ 0.70+ 0.55), II 2.90 (0.80+ 0.95+ 0.65+ 0.50), III 2.50 (0.70+ 0.75+ 0.60+ 0.45), IV 3.00 (0.80+ 1.00+ 0.70+ 0.50); tibia spines: 2-2-1-1; Tm I: 0.58; Tm IV present.

Male palp ( Figs. 6 E-G): Tibia about twice wider than long in retrolateral view, anterioral margin between dorsal process and lateral process bulged, with row of spines ( Fig. 6C ). Tibia trichobothria: one prolateral, two retrolateral. Paracymbium U-shaped ( Fig. 6D ), in retrolateral view, with thumb-shaped proximal arm, main part rising into lobe, bearing several long hairs. Distal suprategulum apophysis (DSA) wide and truncate, with triangular lateral apophysis (LSA) at base ( Figs. 6 H-I). Embolic division marked by well-developed radix ( Figs. 6 H- I): posterior part elongating into tail-piece (TP), anterior part divided into two processes, anterior radix process (ARP) and lateral radix process (LRP), strongly sclerotized, armed with many teeth. The former convex and teeth scattered on the outside surface, the latter subrectangular in prolateral view ( Fig. 6F ), dorsally concave and teeth interspersed on the dorsal surface. Embolus originated from radix, long and well sclerotized. Terminal apophysis (TA) fist-shaped. Lamella characteristica transparent, with two horn-like tips.

Description of female. – Total length: 2.37. Carapace: 0.90 long, 0.75 wide. Abdomen: 1.60 long, 1.10 wide. Carapace brown, without any obvious modification. Chelicerae with six promarginal and five retromarginal teeth. Abdomen gray, with white pattern. Lengths of legs: I 3.11 (0.91+ 1.00+ 0.70+ 0.50), II 2.87 (0.83+ 0.90+ 0.67+ 0.47), III 2.33 (0.70+ 0.70+ 0.50+ 0.43), IV 3.50 (0.93+ 1.33+ 0.87+ 0.37); tibia spines: 2-2-1-1; Tm I: 0.53; Tm IV present. Other somatic characters as in male.

Epigynum ( Figs. 7 A-F): protruding with well-developed ventral plate and dorsal plate, the former opened and the latter extending to the ventral surface and can be seen in ventral and caudal views. In lateral view ( Fig. 7D ) epigynum looks like bird mouth.

Remarks. – The present species very similar to Nasoona prominula Locket, 1982 in the pattern of embolic division and epigynum, and accordingly it should be placed in the genus Nasoona Locket, 1982 . Males of N. eustylis ( Simon, 1909) new combination, differ from those of N. prominula in: 1). Cephalic portion of N. prominula ( Locket, 1982: fig. 22) elevated abruptly, the lobe partly above the ocular area, bearing a prominent forward-directed spine frontally and several bending bristles at top, versus that of the former rising slowly and the lobe entirely behind the ocular area, bearing a prominent forward-directed spine at top, and bending bristles behind ( Fig. 6A ); 2). The prominent forward-directed spine with a hooked tip in the former ( Fig. 6A ), versus in N. prominula not; 3). Clypeus of N. prominula backward, but in N. eustylis straight; 4). The apical part of distal suprategulum of N. prominula figured by Locket (1982: Figs. 27) getting narrowed, versus in N. eustylis almost truncate ( Figs. 6 H-I). 5). Embolic division in retrolateral view compared with that figured by Locket (1982: Fig. 27), anterior part of radix in N. prominula with serrated margin, versus in N. eustylis , as described above, anterior part of radix strongly sclerotized and armed with many teeth on the suface; in N. eustylis , lamella with a biangulate apex, terminal apophysis blunt and fist-shaped, versus in N. prominula , lamella with a obtuse tip, terminal apophysis shovel-shaped and truncate, more prominent than lamella.

Distribution. – Vietnam (Ha Jiang, Cao Bang, Son Tay).

Figures

Fig. 6, Nasoona eustylis (Simon, 1909). A, carapace, lateral view; B, left chelicera, frontal view; C, palpal tibia, dorsal view; D, paracymbium; E, left male palp, retrolateral view; F, left male palp, prolateral view; G, left male palp, ventral view; H, embolic division, ventral view; I, embolic division, dorsal view. [Scale bars: 0.1mm].

Fig. 7, Nasoona eustyliis (Simon, 1909). A, epigynum, frontal view; B, epigynum, ventral view; C, epigynum, caudal view; D, epigynum, lateral view; E, vulva, dorsal view; F, vulva, caudal view. [Scale bars: 0.1mm].

Fig. 1, Erigone brevipes, new species. A, carapace, lateral view; B, carapace, dorsal view; C, male left chelicera, frontal view; D, left male palp, retrolateral view; E, left male palp, prolateral view; F, left male palp, ventral view; G, embolic division, ventral view; H, palpal tibia, dorsal view; I, epigynum, ventral view; J, vulva, dorsal view. [Scale bars: 0.1mm].

Fig. 2, Erigone grandidens, new species. A, carapace, lateral view; B, male left chelicera, frontal view; C, palpal tibia, retrolateral view; D, palpal tibia, dorsal view; E, left male palp, retrolateral view; F, left male palp, ventral view; G, left male palp, prolateral view; H, embolic division, ventral view; I, epigynum, ventral view; J, vulva, dorsal view. [Scale bars: 0.1mm].