Opadometa, ARCHER, 1951

Álvarez-Padilla, Fernando & Hormiga, Gustavo, 2011, Morphological and phylogenetic atlas of the orb-weaving spider family Tetragnathidae (Araneae: Araneoidea), Zoological Journal of the Linnean Society 162 (4), pp. 713-879 : 788-790

publication ID	https://doi.org/ 10.1111/j.1096-3642.2011.00692.x
DOI	https://doi.org/10.5281/zenodo.10545814
persistent identifier	https://treatment.plazi.org/id/7D5E87AD-C022-5549-FCFA-4D54D289F9CA
treatment provided by	Valdenar
scientific name	Opadometa
status

Treatment

OPADOMETA ARCHER, 1951 ( FIGS 5A, B View Figure 5 , 92–95 View Figure 92 View Figure 93 View Figure 94 View Figure 95 )

Type species: Opadometa grata (Guérin, 1838) . The type specimen depository of Epeira grata is unknown. Diagnosis: Opadometa can be distinguished from other tetragnathids by the following combination of characters: female tibia IV with a brush of macroseta on the distal third ( Simon, 1894: fig. 817); fourth femora with two parallel rows of trichobothria with branched shafts ( Fig. 93E, F View Figure 93 ); epigynum flat with a triangular atrium and soft spermathecae ( Figs 94A View Figure 94 , 95E View Figure 95 ); male cheliceral anterior surface armed with many macrosetae ( Fig. 95D View Figure 95 ); conductor fused to the tegulum ( Fig. 95C View Figure 95 ); and by having the adult male size less than half the size of the females.

Description: Female: body length is c. 12.0 mm. Cephalothorax fovea formed by two short transverse grooves ( Fig. 93A View Figure 93 ). Ocular area lower carapace lateral margins ( Fig. 93B, C View Figure 93 ). Labium trapezoidal, wider than long, and rebordered. Sternum as wide as long ( Fig. 93D View Figure 93 ). Anterior surface of chelicerae smooth; boss present. Secondary eyes with canoe-shaped tapetum. Eyes subequal in size, lateral eyes slightly smaller, juxtaposed, and on a tubercle. Clypeus less than one AME diameter. Abdomen longer than wide, covered with silver guanine patches, and anteriorly projected. Booklung cuticle smooth ( Fig. 92A View Figure 92 ). Tracheal spiracle near the spinnerets, almost without accessory glands ( Fig. 92C, E View Figure 92 ). ALS with c. 50 piriform spigots ( Fig. 92A View Figure 92 ). PMS with three aciniform spigots between the cylindrical and minor ampullate silk gland spigots but without any aciniform spigots over the anterior surface ( Fig. 92D View Figure 92 ). PLS with c. 20 aciniform spigots roughly arranged in two parallel lines; distal end of aggregate spigots embracing tip of flagelliform spigot ( Fig. 92F View Figure 92 ). Epigynal plate flat and triangular in shape ( Fig. 93A View Figure 93 ); copulatory openings ventrally orientated, located at the middle base of the atria and in the shape of short longitudinal grooves ( Figs 94A View Figure 94 , 95E View Figure 95 ). Spermathecae walls weakly sclerotized ( Fig. 94B, D View Figure 94 ). Copulatory ducts are more than half the spermathecae length but less than its total length, cuticle weakly sclerotized. Fertilization ducts coiled and sclerotized at their terminal part ( Fig. 95E View Figure 95 ). Accessory glands concentrated over the ducts, with their bases slightly wider than the duct ( Fig. 94E, F View Figure 94 ).

Male: considerably smaller than the female, 7.0 mm body length, somatic morphology similar to a male of L. venusta except that the chelicerae are proportionally longer and the macrosetae on the anterior surface are larger ( Fig. 95D View Figure 95 ). Male palpal patella without macrosetae. Cymbial dorsobasal process present, longer than more than half the cymbial width and perpendicular to the cymbium longitudinal axis ( Fig. 95A View Figure 95 ). Paracymbium hook-shaped, without apophyses and considerably shorter than the cymbium length ( Fig. 95C View Figure 95 ). Tegulum roughly oval with an ectally displaced subtegulum ( Fig. 95C View Figure 95 ). Conductor rigid, with sclerotized edges, bearing a basal apophysis. Conductor-tegulum attachment well sclerotized ( Fig. 95C View Figure 95 ). Embolus base rectangular, longer than wide; embolus flexible and weakly sclerotized. Sperm duct path convoluted with five coils ( Fig. 95B View Figure 95 ).

Natural history: Opadometa has two described species (and eight subspecies), distributed in the South-East Asian tropics ( Simon, 1894; Chrysanthus, 1963, 1975). These spiders build vertical webs (> 45°), with c. 30 radii, c. 30 spiral turns, and open hubs ( Fig. 5A, B View Figure 5 ). They are found along rivers, roads, or in the low vegetation of open spaces.

Taxonomy: The monophyly of Opadometa has never been tested or its taxonomy revised. The males of Opadometa species are extremely rare in collections and in overall morphology resemble a small Leucauge species. In contrast, female specimens are very abundant. Our diagnosis and description of this genus are based in specimens of a species similar to Opadometa grata ( Chrysanthus, 1963, 1975). Data on Opadometa fastigata were taken from Simon (1894). Both our data sets (morphology plus behaviour and these data combined with DNA sequences) suggest that Opadometa is sister to Leucauge .