Yobius haywardi (Chamberlin, 1945)

Yobius haywardi Chamberlin 1945: 154; Mercurio 2010: 45. The description is brief and lacking relevant details. According to Chamberlin (1945) the type is uniformly yellow, 7.5 mm long. Antennae with 35 or 36 articles, 3+3 coxosternal teeth, pores 2, 2, 2, 2 (Chamberlin, 1945). The type specimen, a female, is in the collection of the USNM, and is mounted on a microscope slide. The length is as Chamberlin (1945) states in the original description, the coxosternal teeth are 3 + 3 and the coxal pore formula is 2, 2, 2, 2. However, the antennae, both of which appear to be complete, each have only 29 articles. The posterior margins of the tergites are straight and none of the tergites are produced. Coxal spines are present on the 15th coxae. The specimen lacks all legs except 10 – 12 on the right side and 12 – 14 on the left side, so Chamberlin’s statement that all the tarsi are biarticulate is questionable, unless legs were lost before the specimen was mounted but after it was studied for description. Tarsi 13 and 14 are definitely biarticulate, but the supposed joints on tarsi 11 and 12 are incomplete, and tarsus 10 is not divided. Observing the incomplete articulations of tarsi 11 and 12 may have led Chamberlin to assume that the missing, more anterior legs would also be bitarsate. The gonopod is 3-segmented, the basal segment having two well-developed spurs, but the specimen may not be fully mature.

Y Mountain, above the campus of Brigham Young University (Utah), is specific enough of a type locality to make recollection possible, but until then, the status of Y. haywardi is dubious, due to the incomplete nature of the type, which raises doubts about the most distinctive character, biarticulate tarsi on all legs. Thus Y. haywardi is probably a species of Buethobius, but a definitive decision must wait for the collection and study of topotypical specimens.