Plebs patricius, Joseph & Framenau, 2012

Joseph, Mathew M. & Framenau, Volker W., 2012, Systematic review of a new orb-weaving spider genus (Araneae: Araneidae), with special reference to the Australasian-Pacific and South-East Asian fauna, Zoological Journal of the Linnean Society 166 (2), pp. 279-341 : 321-324

publication ID	https://doi.org/ 10.1111/j.1096-3642.2012.00845.x
persistent identifier	https://treatment.plazi.org/id/EB7687FC-FFBF-8557-7615-FF7CFA5DE603
treatment provided by	Marcus
scientific name	Plebs patricius
status	sp. nov.

Treatment

PLEBS PATRICIUS View in CoL SP. NOV.

ELITE GRASS ORB- WEAVER ( FIGS 26–28 View Figure 26 View Figure 27 View Figure 28 , 31 View Figure 31 )

Types: Holotype. ♂ from Victoria ( Australia), Yarra Ranges National Park , ‘ The Beaches’, near Marysville, 37°29 ′ 08 ′′ S, 145°49 ′ 54 ′′ E, 18.iv.2006, M.G. Rix, sifting leaf litter and beating low vegetation ( NMV K11080 View Materials ) GoogleMaps . Paratype. ♀ from Victoria ( Australia), Phil- lips Track , 0.5 km north of Triplet Falls, Otway Ranges, 38°40 ′ 42 ′′ S, 143°29 ′ 00 ′′ E, 30.i.1995, G. Milledge, direct search, Nothofagus cunninghamii forest ( NMV 11089) GoogleMaps ; five ♀, same data ( NMV K6787 View Materials ) GoogleMaps .

Other material examined: Eleven males, 80 females, and 95 juveniles from 54 records (Appendix S1).

Diagnosis: Male P. patricius differs from other Plebs species in the shape of the median apophysis of the male pedipalp, which is distally widened and protrudes far beyond the cymbium. It has only a single sclerotized apical tip in contrast to most other Plebs in which males have a median apophysis with two sharp tips. The cup-shaped conductor is a very prominent sclerite. The female epigyne scape is elongated and widest at the base, but it is almost always broken off. Similar scape breakage frequencies occur in P. arleneae but the epigyne without a scape differs considerably in both species (compare Fig. 11E View Figure 11 and Fig. 28F View Figure 28 ). Description

Male: Based on male holotype. Carapace light orange-brown ( Fig. 26A View Figure 26 ), glabrous with the exception of sparse white setae mainly in cephalic area and in a narrow band along lateral margins, one light brown bristle behind PE; fovea shallow, crossshaped, longer than wide. Chelicerae orange-brown; a few black setae mainly in apical half; four promarginal teeth and three retromarginal teeth. Sternum orange-brown, sparsely covered with brown bristles. Abdomen dorsally glabrous, with a sparse cover of white setae, short humeral humps marked by white pigmentation; covered with greenish-brown pigmentation, interspersed with grey spots ( Fig. 26A View Figure 26 ); venter with greenish-brown pigmentation ( Fig. 26B View Figure 26 ); weakly covered with brown bristles. Spinnerets light brown. Legs orange-brown; scantly spined. Leg formula 1> 2> 4> 3. Pedipalps ( Fig. 28A–C View Figure 28 ): median apophysis protruding far beyond the cymbium, apex widened; tegulum with an apical protrusion; terminal apophysis with an unsclerotized thin tip, base sinuous; embolus with a twisted sclerotized tip; conductor very prominent, cup-shaped.

Dimensions: total length (excluding chelicerae) 3.82. Carapace length 1.94, width 1.58, height 0.69. Eyes: AME 0.15, ALE 0.12, PME 0.12, PLE 0.12, AME–AME 0.13, AME–ALE 0.19, PME–PME 0.04, PME–PLE 0.23, PLE–ALE 0.02, MOQ width front 0.42, MOQ width back 0.33, MOQ length 0.29, eye group width 0.88. Sternum length 0.79, width 0.67. Abdomen length 2.42, width 1.58. Pedipalp: femur 0.39, patella + tibia 0.31, tarsus 0.73, total 1.43. Leg I: femur 2.23, patella + tibia 2.66, metatarsus 1.58, tarsus 0.73, total 7.20. Leg II: femur 2.04, patella + tibia 2.35, metatarsus 1.46, tarsus 0.58, total 6.43. Leg III: femur 1.04, patella + tibia 0.92, metatarsus 0.69, tarsus 0.35, total 3.00. Leg IV: femur 1.31, patella + tibia 1.54, metatarsus 0.92, tarsus 0.39, total 4.16.

Variation (range): TL 3.15–3.82; CL 1.45–1.94; CW 1.15–1.58; AL 1.64–2.42; AW 1.21–1.58; N = 4. Plebs patricius males exhibit a remarkable colour variation ranging from blackish ( Fig. 26A View Figure 26 ) to brownish ( Fig. 26E, F View Figure 26 ) specimens from Victoria to a totally different glabrous abdominal colour pattern in the Tasmanian specimens examined ( Fig. 26C View Figure 26 ).

Female: Based on paratype NMV K6787. Carapace orange-brown, with a mid-dorsal band of darker pigmentation that is wider in the cephalic area and tapers towards the thoracic area (( Fig. 27A View Figure 27 ); moderately covered with white setae, which are more prominent in the cephalic area as well as in the mid-dorsal pigmented area; fovea Y-shaped. Chelicerae as male; four promarginal teeth and three retromarginal teeth. Sternum dark brown, anterior mid region orangebrown; sparsely covered with brown bristles. Abdomen dorsally glabrous, with a sparse cover of white setae, short humeral humps; greenish-brown foliar pattern with a triangular off-white pigmentation in the anterior mid-dorsal area ( Fig. 27A View Figure 27 ); venter as male, a ring of white pigmentation around the spinnerets ( Fig. 27B View Figure 27 ). Spinnerets light brown. Legs orange-brown with dark annulations, uniformly covered with short spines. Leg formula 1> 2> 4> 3. Epigyne scape elongated, widest at the base ( Fig. 28E View Figure 28 ); spermathecae spherical ( Fig. 28D View Figure 28 ).

Dimensions: total length (excluding chelicerae) 4.79. Carapace length 1.94, width 1.70, height 0.96. Eyes: AME 0.13, ALE 0.12, PME 0.13, PLE 0.12, AME–AME 0.12, AME–ALE 0.25, PME–PME 0.06, PME–PLE 0.27, PLE–ALE 0.02, MOQ width front 0.33, MOQ width back 0.33, MOQ length 0.42, eye group width 0.90. Sternum length 0.48, width 0.42. Abdomen length 3.33, width 2.06. Palp: femur 0.61, patella + tibia 0.61, tarsus 0.55, total 1.77. Leg I: femur 2.12, patella + tibia 2.42, metatarsus 1.58, tarsus 0.67, total 6.79. Leg II: femur 2.00, patella + tibia 2.06, metatarsus 1.33, tarsus 0.55, total 5.94. Leg III: femur 1.15, patella + tibia 1.03, metatarsus 0.67, tarsus 0.48, total 3.33. Leg IV: femur 1.88, patella + tibia 1.94, metatarsus 1.27, tarsus 0.55, total 5.64.

Variation (range): TL 4.12–5.15; CL 1.82–2.12; CW 1.45–1.82; AL 2.55–3.88; AW 1.70–2.12; N = 5. In the samples we examined, Victorian specimens are darker in coloration ( Fig. 27A View Figure 27 ) in comparison to the specimens from Tasmania ( Fig. 28C, D View Figure 28 ) in which the abdomen has an almost completely white dorsal, triangular shield.

Distribution: South-eastern Australia (Tasmania, Victoria) ( Fig. 31 View Figure 31 ).

Life history and habitat preferences: Mature spiders have been collected from September through to April, with highest numbers from November to February. Plebs patricius appears to be a forest species; it was found in southern beech ( Nothofagus cunninghamii ) and eucalypt forest, but also in shrubs or heath, sometimes near woodlands.

Etymology: The specific epithet is a noun in apposition (patricius in Latin – noble men) and is an antonym to the genus name Plebs , referring to its fairly rare occurrence with a limited distribution in Australia.