Stertinius senja, Dhiya’Ulhaq, 2025

Stertinius senja Dhiya’ulhaq sp. nov.

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Figs 47–50 View Fig View Fig View Fig View Fig

Diagnosis

Males of Stertinius senja Dhiya’ulhaq sp. nov. resemble those of Stertinius nobilis (Thorell, 1890) by short, relatively straight embolus and rounded cymbial process, but can be easily distinguished by having subtriangular, anterior tegular lobe ( Fig. 48B, D View Fig vs absent in S. nobilis [ Prószyński 1984: fig. 78]). Females resemble those of Stertinius borneensis Logunov, 2018 by genitalia but can be distinguished by posterior chambers of spermathecae bent at almost right angle in posterior view ( Fig. 50D View Fig vs lightly curved in S. borneensis [ Logunov 2018: fig. 3]); absence of central pocket (present in S. borneensis [ Logunov 2018: fig. 2]); and dark abdominal markings consisting of thick median stripe and five dark lateral stripes ( Fig. 49A, C View Fig vs reticulate in anterior half and covering most of posterior half [ Logunov 2018: fig. 5]).

Etymology

The specific epithet is taken from the Indonesian word ‘ senja ’ meaning ‘twilight’ or ‘sunset’, as the yellow setae and iridescent scales of this species are reminiscent of the twilight during sunset. Noun in apposition.

Material examined

Holotype

INDONESIA – Jambi Province • ♂; Batang Hari, Bajubang, Pompa Air ; 1°49′33.3″ S, 103°17′38.1″ E; elev. 51 m; 14 May 2013; J. Drescher leg.; canopy fogging in jungle rubber plantation; GOET 2013_ HJ2.1_AraSalt069N_011 (to be transferred to MZB). GoogleMaps

Paratypes

INDONESIA – Jambi Province • 1 ♀; same data as for holotype; GOET 2013_HJ2.1_AraSalt069N_012 (to be transferred to MZB) GoogleMaps • 3 ♂♂, 7 ♀♀; same data as for holotype; ZMH ZMH-A0031839 to ZMH-A0031848 GoogleMaps • 2 ♂♂, 3 ♀♀; same data as for holotype; GOET 2013_HJ2.2_AraSalt069N_001 to 2013_HJ2.2_AraSalt069N_005 (deposited at SMF) GoogleMaps • 1 ♂, 2 ♀♀; Batang Hari , Bajubang , Sungkai ; 1°50′8.7″ S, 103°18′00.5″ E; elev. 56 m; 5 Jun. 2013; J. Drescher leg.; canopy fogging in jungle rubber plantation; GOET 2013 _HJ3.1_AraSalt069N_001, 2013_HJ3.1_AraSalt069N_002, 2013_HJ3.2_ AraSalt069N_001 (deposited at SMF) GoogleMaps .

Description

Male ( Figs 47–48 View Fig View Fig )

MEASUREMENTS. Total length 2.94. Carapace length 1.41; width 1.28. Opisthosoma length 1.53; width 1.13. Diameter of eyes: AME 0.36; ALE 0.16; PLE 0.14. Interdistances between eyes: ALE–ALE 0.81; ALE–PLE 0.62; PLE–PLE 1.08. Clypeus height 0.02. Leg measurements: leg I 2.11 (0.73, 0.35, 0.53, 0.27, 0.23); leg II 1.47 (0.50, 0.18, 0.31, 0.26, 0.22); leg III 1.38 (0.51, 0.20, 0.24, 0.24, 0.19); leg IV 1.80 (0.65, 0.26, 0.36, 0.28, 0.25).

HABITUS AND COLORATION. Carapace box-shaped, posteriorly wider, reddish-brown; covered in yellow setae dorsally and white setae on lateral margins and clypeus. Chelicerae reddish-brown, dentition: two promarginal, one retromarginal. Opisthosoma oval; dorsally covered in yellow scutum as well as long, lobed dark marking along middle; five pairs of faint dark stripes on lateral side; dark median area on ventral side; anterior spinnerets dark-gray; posterior lateral spinnerets pale with long median segment. Leg I much stouter than other legs, with very broad femora, colored as carapace, covered in flat, iridescent scales; rest of legs light-brown. Spinnerets: PLS elongated, pale; ALS half of PLS length, light-brown.

PALP ( Fig. 48 View Fig ). Dorsal surface of palp covered in iridescent flat setae. Tibia length-to-width ratio 1.30. RTA as long as tibia, tapering to rounded apex, obliquely tilted dorsally. Cymbium rather broad, posterior margin oblique; cymbial process large, semicircular, partly hidden by RTA. Tegulum oval, possessing subtriangular anterior lobe. Sperm duct following margins of bulb, starting out broad on retrolateral margin, becoming thin on prolateral margin. Embolus arising at 11:00 position, thorn-shaped.

Female ( Figs 49–50 View Fig View Fig )

MEASUREMENTS. Total length 2.81. Carapace length 1.24; width 1.06. Opisthosoma length 1.57; width 1.04. Diameter of eyes: AME 0.19; ALE 0.13; PLE 0.12. Interdistances between eyes: ALE–ALE 0.65; ALE–PLE 0.49; PLE–PLE 0.89. Clypeus height 0.02. Leg measurements: leg I 1.46 (0.55, 0.24, 0.34, 0.14, 0.19); leg II 1.20 (0.38, 0.15, 0.27, 0.19, 0.21); leg III 1.02 (0.39, 0.10, 0.22, 0.14, 0.17); leg IV 1.56 (0.55, 0.18, 0.33, 0.25, 0.25).

HABITUS AND COLORATION. Female habitus as in male, except following: opisthosoma dorsally covered in six small scuta over sigillae; lateral dark markings on opisthosoma longer and more prominent; leg I not as stout as in male, colored lighter than carapace.

EPIGYNUM ( Fig. 50 View Fig ). Epigynal plate oval, wider than long. Copulatory openings small, widely separated from each other. Copulatory ducts short. Spermatheca two-chambered; anterior chamber large, oval. Posterior spermatheca kidney-shaped, diameter approximately half diameter of anterior spermatheca, bent at almost right angle in posterior view; inlet of posterior spermatheca right next to inlet of anterior spermatheca. Central pocket absent. Fertilization ducts short, half length of posterior spermatheca and arising from ventral side of it, diagonally oriented.

Distribution

Sumatra: Jambi Province.

Natural history

All specimens were collected by canopy fogging in jungle rubber plantations and are considered arboreal.