Plebs mitratus Simon 1895
Creators: name: Paul, Jimmy
name: Sankaran, Pradeep M.
name: Joseph, Mathew M.
name: Sebastian, Pothalil A.
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Araneidae
Plebs
Plebs mitratus

description: Plebs mitratus (Simon, 1895)
(Figs 1A–B, 2A–L)
Araneus mitratus Simon, 1895: 805 (description of ♀).
Araneus mitratus Bonnet, 1955: 545.
Araneus mitratus Sherriffs, 1918: 60, 63–64 (description of ♀ and immature Ƌ). Araneus mitratus Sherriffs, 1919: 241 –242, 244 (description of ♀ and immature Ƌ). Plebs mitratus Joseph & Framenau, 2012: 333, Figs. 34A–F (neotype designation, (WAMT109510); description of ♀).
Material examined. India: Kerala: Idukki, Nayamakkadu Shola near Eravikulam National Park, 10o08'57.54''N, 77o04'56.69''E, 1875 m, M.S. Pradeep leg., 22 March 2015, from web among shrubs, by hand, 2♂, 9♀ (ADSH 912710 A); Wayanad, near Heart Lake in Chembra peak, 11o32'45.18''N, 76o05'03.97''E, 1140m, Jimmy Paul leg., 30 July 2015, from web among shrubs, by hand, 1 ♂ (ADSH 912710 B); Idukki, Anamudi Shola National Park, 10°11'58.75''N, 77°11'30.11''E, 1740 m, Mathew M. Joseph leg., 25 August 2015, from web among shrubs, by hand,1♂ (ADSH912710C).
Diagnosis. Plebs mitratus is most similar to P. eburnus (Keyserling, 1886) but can be separated from the latter by the following combination of characters. In males, embolic tip directed at twelve o’clock position in ventral view whereas in P. eburnus, embolic tip directed at two o’clock (Fig. 2A), conductor wider than P. eburnus in ventral view (Fig. 2A), two ventral stout setae on each coxa IV whereas in most P. eburnus each coxa IV bears three ventral setae (Fig. 2L). In females, scape with basal wrinkles whereas in P. eburnus the entire scape wrinkled and medially wide epigynum which in P. eburnus widest at posteriorly (compare Figs 2A–C with Joseph & Framenau 2012: figs. 4A, D, 8A, E). Females of P. mitratus can be separated from the females of P. himalayaensis, the only Indian congener, by less wrinkled and straight scape whereas the scape in P. himalayaensis strongly wrinkled with median kink (compare Fig. 2C with Tikader & Bal 1981: figs. 108–109 and Tikader 1982: figs. 445–446).
Description. Male (ADSH912710A). Carapace pear-shaped. Fovea cross–shaped. Single bristle behind each PLE. Chelicerae with four promarginal and three retromarginal teeth. Abdomen subtriangular, with less prominent humeral humps than that of females, with inconspicuous ventral inverted U-shaped white pattern and with paired conspicuous white spots antero-lateral to the spinnerets. Leg I with coxal spur and corresponding femoral groove on leg II; coxae of leg IV ventrally with paired stout setae; leg formula 1>2>4>3. Pedipalp (Figs 2A–B). Cymbium with a baso-prolateral spur (Fig. 2A). Paracymbium simple, retrolaterally curved, lying in close contact with subtegulum (Figs 2A–B). Tegulum with prominent tegular protrusion (Figs 2A–B). Median apophysis massive with bulbous basal arch, distal half cup-shaped with two apical tips (Fig. 2A). Radix with dorsally visible apical part (Fig.2B). Terminal apophysis with a sinuous base and an unsclerotized tip (Fig. 2A). Embolus with medio-prolateral protrusion, with sclerotized tip directed at twelve o’ clock position in ventral view (Fig.2A). Paramedian apophysis with spatula-like tip (Fig. 2A). Conductor broad, ovate with sclerotized tip (Fig. 2A).
Dimensions: Total length 5.22. Carapace length 2.44, width 2.07. Eye diameter: ALE 0.10, AME 0.13, PLE 0.11, PME 0.13. Eye interdistances: AME–AME 0.16, AME–ALE 0.21, PME–PME 0.12, PME–PLE 0.38, PLE–ALE 0.03. Abdomen length 2.78, width 2.27. Pedipalp: femur 0.43, patella + tibia 0.44, tarsus 0.97, total 1.84. Leg I: femur 2.76, patella + tibia 3.17, metatarsus 1.65, tarsus 0.83, total 8.41. Leg II: femur 2.29, patella + tibia 2.66, metatarsus 1.60, tarsus 0.79, total 7.34. Leg III: femur 1.50, patella + tibia 1.43, metatarsus 0.85, tarsus 0.55, total 4.33. Leg IV: femur 2.13, patella + tibia 2.22, metatarsus 1.51, tarsus 0.69, total 6.55.
Variation (range): TL 4.98–5.52; CL 2.26–2.44; CW 2.04–2.21; AL 2.72–3.07; AW 2.03–2.27; N =3.
Female (ADSH912710A). In most details like male except the followings: brown bristle behind each PLE absent. Fovea Y- shaped. Cheliceral promarginal teeth equally spaced. Abdomen subtriangular with prominent humeral humps and conspicuous ventral inverted U-shaped white pattern and with paired white spots antero-lateral to spinnerets. Leg formula 1>4>2>3. Genitalia (Figs 2C–G): Epigymum medially wide composed of paired elongated lateral plates and a posterior oval plate, all remained fused antero-medially (Fig. 2C). Scape elongated, straight, with conspicuous wrinkles basally (Fig. 2F), wide at base (Fig. 2C). Copulatory openings medium-sized, crescent-like, medially placed (Fig. 2C). Copulatory ducts sclerotized. Spermathecae reniform, confronting each other in dorsal view (Figs 2D, G). Fertilization ducts short, originate apically to copulatory ducts (Figs 2D–E, G).
Dimensions: Total length 7.87. Carapace length 2.94, width 2.73. Eye diameter: ALE 0.12, AME 0.15, PME 0.14, PLE 0.12. Eye interdistances: AME–AME 0.18, AME–ALE 0.48, PME–PME 0.14, PME–PLE 0.59, PLE–ALE 0.07. Abdomen length 4.93, width 3.93. Palp: femur 0.92, patella + tibia 1.06, tarsus 1.13, total 3.11. Leg I: femur 3.56, patella + tibia 4.18, metatarsus 2.40, tarsus 0.93, total 11.07. Leg II: femur 3.07, patella + tibia 3.45, metatarsus 2.18, tarsus 0.93, total 9.63. Leg III: femur 1.94, patella + tibia 1.91, metatarsus 1.19, tarsus 0.70, total 5.74. Leg IV: femur 3.23, patella + tibia 3.39, metatarsus 2.32, tarsus 0.85, total 9.79.
Variation (range): TL 6.33–7.87; CL 2.37–2.94; CW 2.28–2.73; AL 3.81–4.93; AW 2.74–3.93; N =9.
Remarks. All examined specimens were collected from three different sites of tropical montane wet temperate forests (Shola forests) (Fig. 1C). Specimens from these three Shola forests showed considerable variation in body pattern, colouration and aspects of male and female genitalia (see Figs 2A, D, H, J–K). Male palp of specimen from Chembra peak exhibits variations from the described specimen by the following aspects (characters): shape of the conductor, size and orientation of tegular protrusion and shape and orientation of unsclerotized angular tip of terminal apophysis (Figs 2A, H). Even specimens from the same Shola forest (Nayamakkadu Shola) revealed intraspecific variations (Figs 2D, J– K). A mating plug was also observed in five of the nine female specimens collected from the Nayamakkadu Shola (Fig. 2I). The plug, which was formed of an amorphous material (secretory plug), was found to be inserted in the copulatory openings (right or left or both) and in the clefts between the lateral and median plates and extended posteriorly to cover the entire area of the median plate. A mating plug was clearly visible in the right copulatory opening and in the left cleft of P. eburnus, although Joseph & Framenau (2012) had not mentioned its occurrence in the genus (Joseph & Framenau 2012; fig. 4D).
description: Published as part of Paul, Jimmy, Sankaran, Pradeep M., Joseph, Mathew M. & Sebastian, Pothalil A., 2016, The male of the orb-weaving spider Plebs mitratus (Simon, 1895) and a redescription of the female (Araneae, Araneidae), pp. 103-106 in Zootaxa 4179 (1) on pages 103-106, DOI: 10.11646/zootaxa.4179.1.4, http://zenodo.org/record/163712