Leptoctenus byrrhus
Simon, 1888
Leptoctenus byrrhus is a medium-sized wandering spider ( Ctenidae) first described by Eugène Simon in 1888. It occurs in southern Texas and northeastern Mexico, and has been found in diverse microhabitats including leaf litter, under rocks, and occasionally inside human dwellings. The exhibits a distinctive posture with the first pair of legs held forward like .
Pronunciation
How to pronounce Leptoctenus byrrhus: /lɛptoʊkˈtɛnəs ˈbɪrəs/
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Identification
The elevated distinguishes Leptoctenus byrrhus from many superficially similar wandering spiders. Microscopic examination reveals diagnostic features: cheliceral fang with only three teeth on the posterior surface (facing rear), and male palpal tibia with excavated region and long bearing sharply recurved extensions. The female is distinctive—wider than long with a long, narrow neck and lateral spurs. The characteristic forward-held first pair of legs, even at rest, provides a behavioral cue.
Appearance
Medium-sized, hairy spider with gray background coloration. Body and legs heavily splotched with dark marks forming two irregular longitudinal lines on the and . Legs display dark rings (two or three per ) when viewed from above. Males reach approximately 10.5 mm body length; females approximately 13.5 mm. The portion of the cephalothorax (behind the ) is elevated relative to the portion. Scopula pads at leg ends are moderately developed.
Habitat
Found in ground-level microhabitats including leaf litter and detritus, under rocks and debris (e.g., plywood sheets), at cave entrances, and in woodrat nests. In Ciudad Victoria, Tamaulipas, Mexico, has been encountered inside houses.
Distribution
Southern Texas, United States and northeastern Mexico. from Mexico.
Behavior
Walks with the first pair of legs extended forward as if functioning as . Often maintains this posture even when at rest, with these legs held off the ground.
Ecological Role
Ground-dwelling in terrestrial .
Human Relevance
Has been encountered inside houses in northeastern Mexico (Ciudad Victoria, Tamaulipas), indicating potential for occurrence.
Similar Taxa
- Other Ctenidae speciesShare general wandering spider including hairy bodies, similar size ranges, and dark patterning; distinguished by technical characters including profile, cheliceral , and genitalic structures
More Details
Etymology
name from Greek lepto- (slender, thin, narrow, graceful, fine) and -ctenus (comb), possibly referring to the calamistrum—a line of fine hairs on the legs
Type specimen
Described by Eugène Simon in 1888 (Annales de la Société entomologique de France 210); type locality in Mexico