Opadometa Archer 1951
Creators: name: Álvarez-Padilla, Fernando
name: Hormiga, Gustavo
Publisher: name: Zenodo
Year: 2011
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Tetragnathidae
Opadometa

description: OPADOMETA ARCHER, 1951 (FIGS 5A, B, 92–95)   
 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); epigynum flat with a triangular atrium and soft spermathecae (Figs 94A, 95E); male cheliceral anterior surface armed with many macrosetae (Fig. 95D); conductor fused to the tegulum (Fig. 95C); 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). Ocular area lower carapace lateral margins (Fig. 93B, C). Labium trapezoidal, wider than long, and rebordered. Sternum as wide as long (Fig. 93D). 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). Tracheal spiracle near the spinnerets, almost without accessory glands (Fig. 92C, E). ALS with c. 50 piriform spigots (Fig. 92A). 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). PLS with c. 20 aciniform spigots roughly arranged in two parallel lines; distal end of aggregate spigots embracing tip of flagelliform spigot (Fig. 92F). Epigynal plate flat and triangular in shape (Fig. 93A); copulatory openings ventrally orientated, located at the middle base of the atria and in the shape of short longitudinal grooves (Figs 94A, 95E). Spermathecae walls weakly sclerotized (Fig. 94B, D). 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). Accessory glands concentrated over the ducts, with their bases slightly wider than the duct (Fig. 94E, F).   
 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). 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). Paracymbium hook-shaped, without apophyses and considerably shorter than the cymbium length (Fig. 95C). Tegulum roughly oval with an ectally displaced subtegulum (Fig. 95C). Conductor rigid, with sclerotized edges, bearing a basal apophysis. Conductor-tegulum attachment well sclerotized (Fig. 95C). Embolus base rectangular, longer than wide; embolus flexible and weakly sclerotized. Sperm duct path convoluted with five coils (Fig. 95B).   
 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). 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.
description: Published as part of Álvarez-Padilla, Fernando & Hormiga, Gustavo, 2011, Morphological and phylogenetic atlas of the orb-weaving spider family Tetragnathidae (Araneae: Araneoidea), pp. 713-879 in Zoological Journal of the Linnean Society 162 (4) on pages 788-790, DOI: 10.1111/j.1096-3642.2011.00692.x, http://zenodo.org/record/5440885