Ochrogramma Gardener and Shelley 1989

Ochrogramma Gardner and Shelley, 1989 Ochrogramma Gardner and Shelley 1989: 194. Type species. Ochrogramma formulosa Gardner and Shelley, 1989, by original designation. Notes. Ochrogramma is superficially similar to Vasingtona. Males of the species of Ochrogramma are usually smaller (10–15 mm) than those of Vasingtona irritans (16–22 mm). In our new interpretation of the gonopods in this subfamily, Ochrogramma is distinct from Vasingtona in having many fewer arborescent processes on the gonopod (Fig. 19, 23, 24)—two species of Ochrogramma may have none—in the reduced and perhaps sometimes absent telopodite (t, Fig. 20), having a rodlike posterior angiocoxite (pac, Fig. 20), and a prominent posterior lobe of the colpocoxite. The hypothesis that the colpocoxite originates from the coxal gland of the eighth legpair is supported by the relatively poorly sclerotized colpocoxites emerging from distinct sockets in this genus (cc, Fig. 20). Gonopod structure is similar among the species, but two of them, O. formulosa Gardner and Shelley, 1989, and O. heterogona Gardner and Shelley, 1989, seem to lack the arborescent processes (“spicules” of Gardner and Shelley) on the anterior surfaces of the anterior angiocoxites. We have not seen specimens of these species. Ochrogramma bentona has the most complex gonopods in the genus while those of O. haigi, O. formulosa and O. heterogona are progressively simpler. Gardner and Shelley (1989) did not give length measurements for females, but we found that females are typically longer than males (17–19 mm in O. bentona). The dorsal yellow stripe typical of the subfamily may be suppressed entirely in Ochrogramma species males, or present only on posterior rings. The gonopod telopodite is seen in only two of the species, O. bentona and O. formulosa. It is highly reduced and rodlike (t, Fig. 20), articulating about one-third of the way distal on the anterior angiocoxite and terminating in several filaments which are likely modified setae. The posterior angiocoxite, evidently missing in O. heterogona, is roughly similar in form to the telopodite (pac, Fig. 21, 22). Flagellocoxites are present in all species and are filamentous and branched (f, Fig. 21). Ochrogramma was considered by Gardner and Shelley (1989) to be distributed entirely to the south of the Columbia River, but this was an artifact of insufficient collecting in Washington. Ochrogramma bentona (Chamberlin, 1952), extends north of the river to the Puget Sound region and Ochrogramma skamania n. sp. is from west central Washington. The other three Ochrogramma species are limited to small areas of Oregon and northern California (Gardner and Shelley 1989, Fig. 220). The meaning of the name Ochrogramma was not discussed by Gardner and Shelley (1989). Both parts of the name come from Greek; ochros a prefix meaning “yellow” and gramma, referring to a “line, writing or drawing” (the root of English words such as grammar, graphics, telegraph, etc.). The combination likely refers to the dorsal yellow stripe.