Two new Gordionus species (Nematomorpha: Gordiida) from the southern Rocky Mountains (USA)

Abstract

The phylum Nematomorpha contains approximately 350 species in 19 extant genera. The genus Gordionus contains 56species, four of which occur in the contiguous United States of America. Here we describe two new Gordionus speciesfrom the southern Rocky Mountains. Worms were collected at three sites in the Santa Fe National Forest in northern NewMexico in the southernmost tip of the Rocky Mountains. Sites consisted of first order streams above 3120m in aspen/pinewoodland. Gordionus lokaaus n. sp. has flat, polygonal or roundish, areoles covering all parts of the body. The male cloa-cal opening is surrounded by broad bristles with stout apexes forming a unique tube-like opening. Adhesive warts aresmall and postcloacal spines are thin and triangular-shaped. Gordionus bilaus n. sp. also has flat polygonal or roundshaped areoles, but has indistinct interareolar furrows making neighboring areoles appear fused. The male cloacal openingis surrounded by stout, finger-like bristles in 2‒3 rows. Adhesive warts are larger and postcloacal spines are broad andmound-shaped. These species double the number known from the state of New Mexico and are the first gordiids described from the southern part of the Rocky Mountains.

A New Species of Gordionus (Nematomorpha: Gordiida) from the Rocky Mountains of New Mexico

“…Eggs and egg strings of many of the other gordiid species listed above can usually be found by searching their natural habitat. Failure to observe mating or eggs in nature has also been noted for G. bilaus and G. lokaaus, both of which also occur in the Rocky Mountains (Begay et al, 2012). It is possible that these high-altitude Gordionus species have a unique mating system which may include overwintering and mating during the spring.…”

“…Extensive search of field sites did not reveal eggs or egg strings. This difficulty has been noted in other Gordionus species (Begay et al, 2012). Thus, measurements of eggs, larvae, and cysts could not be included in this study.…”

“…Despite a recent flurry of taxonomic activity on this group, only about 30 species have been recognized from North America (Schmidt-Rhaesa et al, 2016;Swanteson-Franz et al, 2018). The paucity of diversity within the Nearctic is likely because of a lack of study and sampling effort, and recent new species discoveries in the southern Rocky Mountains and Sky Islands of the American Southwest support this idea (Begay et al, 2012;Swanteson-Franz et al, 2018). To continue our search for new gordiid species, we focused on sampling streams in the Southern Rocky Mountains and discovered another new gordiid in the genus Gordionus.…”

“…The cosmopolitan genus Gordionus contains 58 species (Schmidt-Rhaesa, 1997, 2001bBegay et al, 2012). Six Gordionus species have been reported from the Nearctic.…”

“…Six Gordionus species have been reported from the Nearctic. Two species, Gordionus bilaus Begay et al, 2012 andGordionus lokaaus Begay et al, 2012, were recently described from high-altitude alpine ecosystems within the Rocky Mountains (Begay et al, 2012). Despite these 2 species being distributed near areas of high human activity (hiking trails, picnic area, ski area parking lot), they seemingly went unnoticed for many years.…”