Mecistocephalus evansi

This species has 51 pairs of legs and can reach 38 mm in length. The head is shaped like a rectangle, with nearly the same width in the back as in the front, and features a pair of longitudinal grooves on the surface in front of a straight posterior margin. The mandible features eight pectinate lamellae (comb blades), with six or seven teeth on the first lamella and fourteen teeth on the middle lamellae. The dorsal cephalic plate nearly covers the forcipules. The forcipular sternite has an anterior margin that is almost straight in the middle and features no teeth. This sternite also has no chitin-lines and is more than 1.2 times longer than wide. The first article of the forcipule has a distinct intermediate denticle as well as a distal denticle. The ultimate article of the forcipule lacks a distinct basal denticle. The body is uniform in width for the first four-fifths of its length, then tapers gradually from about the 40th segment to the last segment. The first tergite features two longitudinal impressions that are wide but shallow, and the tergites from the second to the penultimate segments each feature two grooves. The sternites on the anterior part of the trunk, from the second sternite to about the 23rd sternite, feature a distinct median groove that divides into two short branches at the anterior end. …

This species was first described by the French myriapodologist Henry W. Brolemann in 1922. He based the original description of this species on a single female specimen found in the Maysan governorate (formerly Amara province) on the Tigris river in Iraq. Since the discovery of the first specimen, this species has been found in other locations in Iraq, Iran, and Israel. Several specimens have been recorded in Israel, mostly from Mediterranean regions of the Galilee, at higher elevations with lower temperatures and more precipitation. The Israeli specimens include those found in Mount Meron and Gush Halav as well as one found in Be’er Sheva in the Negev desert that may be the result of an anthropogenic transfer. This species has also been found in Gakal Cave in the Kohgiluyeh and Boyer-Ahmad province of Iran, indicating that M. evansi is a troglophile, living in subterranean habitats as well as at the surface. Furthermore, specimens have been found in the Basrah governorate in Iraq, including specimens from the Al-Hartha and Shatt Al-Arab districts. Specimens collected from the Basrah governorate include five males and six females found in 2022 on wet agricultural land, in the soil under palm trees, on the left bank of the Shatt Al-Arab river and in the Al-Hartha district.