Anaxibia folia, Sankaran & Sebastian, 2017

Sankaran, Pradeep M. & Sebastian, Pothalil A., 2017, Anaxibia folia spec. nov. - a new litter-dwelling dictynid spider from India (Araneae: Dictynidae: Dictyninae), Zootaxa 4363 (3), pp. 441-444 : 441-444

Anaxibia folia spec. nov. ( Figs 1– 3 )

Type material: Holotype: Male ( ADSH2831 A), INDIA: Kerala: Malappuram, Nilambur , Canolly’s Plot , 11o16'06.17''N, 76o12'22.21''E, 20 m alt., 16 May 2013, P.M. Sankaran leg., from forest litter, by hand . Paratypes: 1 male, 2 females, 1 juvenile ( ADSH2831 B), same data as for holotype .

Etymology. The specific epithet is a neuter plural in apposition, derived from the leaf litter-dwelling habit of the new species. Latin: folium = leaf.

Diagnosis. Anaxibia folia spec. nov. is most similar to Anaxibia pictithorax ( Kulczyński, 1908) , but can be separated from the latter by the following combination of characters: cymbial caudal lobe (CL; Fig. 2B, D ) almost straight and remaining covered by tibia in ventral view (cymbial caudal lobe of A. pictithorax with strong baso-prolateral bend and visible in ventral view), tibia with ventral bulging (tibia of A. pictithorax lacks ventral bulging), dorsal tibial apophysis (DTA; Fig. 2D ) short and distant from cymbial caudal lobe ( A. pictithorax with broad DTA lying close to cymbial caudal lobe) and epigyne with sclerotised horizontal plates (SHP; Fig. 2E ) and without lateral foveae (epigyne of A. pictithorax with lateral foveae and without sclerotised horizontal plates) (compare Figs 2B–E with Kulczyński 1908: plate 23, figs 27–29). Females of A. folia spec. nov. can be separated from the females of A. rebai , the only Indian congener by lacking paired brown or black patches on the posterior half of mid-dorsal opisthosoma and epigyne with sclerotised horizontal plates and without lateral foveae, whereas the posterior half of mid-dorsal opisthosoma of A. rebai with paired conspicuous deep brown or black patches and epigyne with lateral foveae and lacks sclerotised horizontal plates (compare Figs 1B , 2E with Tikader 1966: figs 1a–b).

Description. Male (holotype, Figs 1A, C, E , 2A ). Carapace brownish with dark brown striae, with cephalic region elevated more than thoracic region ( Figs 1A , 2A ). Fovea absent. Ocular area, clypeus, chelicerae, fangs, labium, maxillae, sternum brownish. AER recurved, PER straight; AME black, all others pearly white ( Fig. 1A ). Boss prominent. Cheliceral promargin with three teeth, retromargin with one. Maxillae with reduced scopulae. Sternum covered with black hairs, weak medially; truncate between coxae IV, with blunt tip. Opisthosoma widely oval, creamy white with inconspicuous broad greyish patches, covered with a uniform mat of fine greyish hairs; dorsum provided with two pairs of sigillae ( Fig. 1A ). Anal tubercle prominent ( Fig. 1C ). Cribellum reduced ( Fig. 1C ). Spinnerets creamy white with greenish shades only on posterior lateral spinneret; anterior lateral spinneret widest, posterior lateral spinneret longest ( Fig. 1C ). Legs slender, spineless, setaceous, brownish with green shades; metatarsus IV with reduced calamistrum ( Fig. 1E ). Body length 1.35. Prosoma length 0.56, width 0.50. Opisthosoma length 0.79, width 0.58. Eye diameters: ALE 0.03.

AME 0.04. PLE 0.02. PME 0.02. Eye interdistances: AME–AME 0.02. AME–ALE 0.02. AME–PME 0.02. PME–PME 0.05. PME–PLE 0.06. Clypeus height at AMEs 0.07, at ALEs 0.08. Chelicerae length 0.23. Measurements of pedipalp and legs. Pedipalp 0.60 [0.17, 0.11, 0.09, 0.23], I 1.73 [0.50, 0.18, 0.44, 0.36, 0.25], II 1.57 [0.46, 0.16, 0.37, 0.34, 0.24], III 1.35 [0.40, 0.14, 0.30, 0.30, 0.21], IV 1.52 [0.46, 0.15, 0.35, 0.36, 0.20]. Leg formula: 1243. Pedipalp ( Figs 2B–D ): Palpal segments uniformly brownish, spineless; femur disto-dorsally with a short bulging ( Figs 2C–D , 1 st arrow ); patella retrolaterally with a short, triangular process (PP; Fig. 2B ); tibia with ventral bulging ( Figs 2B–C, 2 nd arrow), distoventrally with short, knob-like ventral tibial apophysis (VTA; Fig. 2C ), with an obliquely oriented, plate-like dorsal tibial apophysis (DTA; Fig. 2D ). Cymbium proximo-prolaterally with a moderately long caudal lobe (CL; Fig. 2B, D ). Tegulum moderately large. Dictynid terminal apophysis stout, medio-retrolaterally placed (dTA; Fig. 2C ), disto-ventrally with a horizontal ridge ( Fig. 2B , 3 rd arrow). Subtegulum small, globular (ST; Figs 2B–C ). Embolus originating prolaterodistally from tegulum, moderately long, with wedge-shaped proximad tip resting near base of conductor (E; Fig. 2C ). Conductor originating retrolatero-proximally from tegulum, unmodified, smoothly curved (C; Figs 2B–C ), with straight basal part and prolaterad apical part (uC, tC; Fig. 2B ).

Female (paratype, Figs 1B, D, F ). Like male except the following. Carapace, ocular area, clypeus, chelicerae, fangs, maxillae, labium, sternum, legs, spinnerets, palps straw coloured ( Fig. 1B ). Opisthosoma lacking greyish patches ( Fig. 1B ). Cribellum well marked, unipartite ( Fig. 1D ). Calamistrum prominent, uniseriate ( Fig. 1F ). Palpal tibiae and tarsi bear spine-like macrosetae. Body length 1.59. Prosoma length 0.60, width 0.51. Opisthosoma length 0.99, width 0.65. Eye diameters: ALE 0.03. AME 0.03. PLE 0.02. PME 0.02. Eye interdistances: AME–AME 0.03. AME–ALE 0.02. AME–PME 0.02. PME–PME 0.05. PME–PLE 0.05. Clypeus height at AMEs 0.05, at ALEs 0.06. Chelicerae length 0.21. Measurements of palp and legs. Palp 0.53 [0.15, 0.08, 0.10, 0.20], I 1.88 [0.57, 0.19, 0.46, 0.41, 0.25], II 1.75 [0.54, 0.18, 0.41, 0.38, 0.24], III 1.54 [0.49, 0.17, 0.33, 0.34, 0.21], IV 1.82 [0.59, 0.19, 0.42, 0.40, 0.22]. Leg formula: 1423. Copulatory organ ( Figs 2E–F ): Epigyne simple, hirsute, widely flat, laterally with distinct, sclerotised, smoothly curved horizontal plates (SHP; Fig. 2E ). Copulatory openings crescent-like, widely separated, lying near to the posterior border of epigyne (CO; Fig. 2E ). Copulatory ducts short, sclerotised, basally wide, basal part remains contiguous with an enlarged sac-like median diverticulum (CD; Fig. 2F ); median diverticulum roughly squarish with anterior concavity, postero-laterally with paired, broad lobes overhanging to the basal part of copulatory ducts (MD, LLMD; Fig. 2F ). Spermathecae small, sclerotised, circular (S; Fig. 2F ). Fertilization ducts narrow, angular, originating postero-laterally from spermathecae (FD; Fig. 2F ).

Distribution. Only known from the type locality ( Fig. 3 ).

Note. Males of A. rebai are misidentified and belonging to Nigma shiprai ( Tikader, 1966) (World Spider Catalog 2017).

Figures

FIGURES 1A–F. Anaxibia folia spec. nov. A–B Habitus, dorsal (A male, B female). C–D Posterior part showing reduced cribellum, anal tubercle and spinnerets, ventral (C male, D female). E Male left metatarsus IV showing reduced calamistrum, retrolateral. F Femaleleft metatarsus IV showing calamistrum, prolateral.Scale bars:A–B 0.5 mm; C–F0.2 mm.

FIGURES 2A–F. Anaxibia folia spec. nov. A Male prosoma, retrolateral.B–D Male left pedipalp(B prolateral, C ventral, D dorsal). E Epigyne,ventral.F Vulva, dorsal.Abbreviations:C—conductor, CD—copulatory duct, CL—cymbial caudal lobe, CO—copulatory opening, dTA—dictynidterminalapophysis,DTA—dorsaltibial apophysis,E—embolus,FD—fertilization duct,LLMD—laterallobe of median diverticulum,MD—median diverticulum,PP—patellar process,S—spermatheca,SHP—sclerotised horizontal plate, STsubtegulum, tC—apicalpart of conductor,T—tegulum,uC—basal part of conductor, VTA—ventral tibial apophysis.Scale bars:A–F, 0.2 mm.Arrows:1indicates femoralbulging,2 tibial bulging, 3 horizontal ridge of dictynid terminalapophysis.

FIGURE 3. Anaxibiafolia spec. nov., type locality.