Thanatus altimontis
Gertsch, 1933
Thanatus altimontis is a running crab spider in the Philodromidae, first described by Gertsch in 1933. As a member of the Thanatus, it shares the characteristic ground-dwelling hunting typical of this group, contrasting with the vegetation-dwelling habits of related slender crab spiders (Tibellus). The occurs in mountainous regions of western North America, with records from the western United States, Mexico, and western Canadian provinces. Like other Thanatus species, it likely overwinters as an and becomes active in early spring, when specimens have been observed basking on warm surfaces.
Pronunciation
How to pronounce Thanatus altimontis: /ˈθænətəs ˌæltɪˈmɒntɪs/
These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.
Identification
Thanatus altimontis can be distinguished from the similar slender crab spider Tibellus (also Philodromidae) by its more robust body build and different stripe pattern on the . Thanatus are ground-dwelling hunters found amid grasses and weeds, whereas Tibellus are almost always found on stems, stalks, grassblades, or leaves. Thanatus altimontis may also be confused with wolf spiders in the genus Schizocosa or Pardosa due to shared longitudinal stripes on the cephalothorax and a dark cardiac mark on the , but differs in arrangement and leg posture. From lynx spiders (Oxyopes), Thanatus lacks the very long leg spines and scrunched ambush posture.
Habitat
Based on the epithet "altimontis" (meaning "of high mountains") and distribution records, this species inhabits montane and subalpine environments. Related Thanatus species are ground-dwelling hunters in grassy areas, meadows, and open with low vegetation. They have been observed on concrete and asphalt surfaces in spring, presumably basking to elevate body temperature.
Distribution
Western North America: United States (including Colorado), Mexico, and Canada (Alberta, British Columbia, Manitoba). The appears to be associated with mountainous regions of the western continent.
Seasonality
Active in spring. Related Thanatus have been observed as in March and April, with specimens found basking on warm surfaces during periods of mild weather. The species likely overwinters as an adult, becoming active when temperatures permit.
Behavior
Ground-dwelling hunting , distinct from vegetation-dwelling philodromids. Specimens have been observed basking on warm surfaces such as concrete paths to elevate body temperature. Like other Thanatus, likely employs sit-and-wait or slow pursuit hunting strategies amid ground vegetation.
Similar Taxa
- TibellusSlender crab spiders in the same (Philodromidae) that share similar coloration but differ in (vegetation-dwelling vs. ground-dwelling), body shape (more slender and flattened), and stripe pattern
- SchizocosaWolf spiders (Lycosidae) that share superficial resemblance in longitudinal stripes and dark cardiac mark, but differ in arrangement and active hunting
- Oxyopes salticusStriped lynx spiders that share grassland and striped pattern, but have very long leg spines, more scrunched posture, and longer '' ( profile)
More Details
Etymology
The epithet "altimontis" derives from Latin, meaning "of high mountains," reflecting the species' montane distribution.