Trachyrhinus

Trachyrhinus Weed, 1892 is a Nearctic genus of Sclerosomatidae found in northern Mexico and parts of the western and midwestern United States.

Taxonomy[]

Phalangium favosum Wood, 1871, by original designation - now Trachyrhinus favosus (Wood, 1871).

(from Cokendolpher, 1981^[2]): "Medium sized phalangioids with hard, coarsely punctate bodies; dorsum with white opalescent spots; with poorly developed lateral sclerites in some specimens. Ocular tubercle approximately equal in length and width, with two well developed rows of pointed tubercles. Chelicerae not enlarged, with tooth on first segment ventrally. Supracheliceral lamellae in the form of two plates. Scent gland pores small, oval to slightly elongated. Coxae, except posterior portions of III, and genital operculum with lateral rows of tri-pointed denticles; rows on genital operculum rarely reduced or absent. Coxae III and IV enlarged in males. Legs long, covered with spines and tubercles; femora I equal to or shorter than length of body, II with one or two pseudo-articulary nodules; tibiae II with pseudosegments. Palpi often with an apophysis on inner distal margins of patellae; tarsi with ventral rows of denticles in males, unarmed in females; claw smooth. Penis alate; shaft long and thin, contracted and bent slightly anterior to alate portion, ending in a sharp tip; alate portion consisting of two sacs opening distally."

MEXICO: Baja California; Chihuahua; Coahuila; Durango; Puebla; San Luis Potosí; Sonora; Tamaulipas; Zacatecas^[3]
USA: Arizona; California; Colorado; Kansas; Minnesota; Montana; Nebraska; New Mexico; North Dakota; Oklahoma; South Dakota; Texas; Utah^[3]

Hallan lists Trachyrhinus sonoranus Chamberlin, 1925 separately, but this species was synonymized with Trachyrhinus marmoratus Banks, 1894 by Goodnight & Goodnight, 1946.
Although there are no formal records of Trachyrhinus from Nuevo León, photographs uploaded to iNaturalist indicate their presence in this state as well. iNaturalist link: https://www.inaturalist.org/taxa/248669-Trachyrhinus
Within the genus Trachyrhinus are apparently two species groups, although these groups lack any formal taxonomic designation. One group, consisting of T. dicropalpus, T. favosus, and T. marmoratus, is characterized by the presence of a palpal apophysis and by having the alate portion of the penis large and expanded. The second group, consisting of T. horneri, T. mesillensis, and T. rectipalpus, is characterized by lacking a palpal apophysis, penis with small alate portion, reduced number and size of lateral tubercles on the ocular tubercle, and by having the distal portions of the palpal tarsi slightly expanded.^[2]

↑ Weed, Clarence M. (1892d) Notes on harvest-spiders. The American naturalist, New York, NY, 26(306), 528–530.
↑ ^2.0 ^2.1 Cokendolpher, J.C. (1981a) Revision of the genus Trachyrhinus Weed (Opiliones, Phalangioidea). The Journal of Arachnology, 9(1), 1–18.
↑ ^3.0 ^3.1 Cokendolpher, J.C. & Lee, V.F. (1993) Catalogue of the Cyphopalpatores and bibliography of the harvestmen (Arachnida, Opiliones) of Greenland, Canada, U.S.A., and Mexico. Privately Published, Vintage Press, Lubbock, Texas, iii + 82 pp.