Protura in Arctic Regions, with Description of Mastodonentomon n. gen. (Acerentomidae, Nipponentominae) and a Key to Known Arctic Taxa

Abstract

Protura are widespread, but their presence in the Arctic was first noted only ca. 70 years ago and is still little acknowledged. This work compiles taxonomic information on proturans in the Arctic regions and adds unpublished data from Northern Siberia. Currently, this fauna is represented by 23 species in two orders and 14 genera. The large cosmopolitan genus Eosentomon is represented by only four species, whereas Acerentomidae is much more diverse, with 19 species in 13 genera (eight Nipponentominae, five Acerentominae). Most of the Arctic species possess a larger number of setae than species living in temperate regions. Based on several unique characters, a new genus, Mastodonentomon, is erected for Nipponentomon macleani, and the species is re-described with the original description supplemented with new characters, including head chaetotaxy, seta length, and porotaxy. Proturan occurrence in the Arctic is limited to Beringia, but the majority of species have restricted distributions and none have been found in both the American Arctic and Siberia. This implies relict origins and high levels of proturan endemism in the Arctic. This emerging view on biogeographical history is, however, hampered by the limited extent of available data, which highlights the need for considerably greater survey efforts. A key to Arctic proturans is provided to facilitate further studies.

The geographic distribution of Protura (Arthropoda: Hexapoda): a review

“…Yamatentomon yamato (Imadaté & Yosii, 1956) in the Siberian tundra (Lena Delta Nature Reserve) at more than 72°19' N; Verrucoentomon imadatei Nosek, 1977 at 70°29'N in Alaska; Nienna chukotka Shrubovych, 2019 at 69°48' N in Russia; Alaskaentomon fjellbergi Nosek, 1977 at 69°30' N in Alaska; Verrucoentomon canadense (Tuxen 1955) at 68°42' and 68°24' N in Canada; Vesiculentomon condei (Tuxen, 1955) at 68°24' N in Canada; Yavanna behanae (Nosek, 1977) at 67°28' N in Alaska; undetermined specimens belonging to genera Acerentulus and Eosentomon in localities over 68° N in Alaska and Canada, respectively. For a complete review of Protura from the Arctic regions see Shrubovych et al (2020). Conversely, the southernmost records of Protura barely reach the 46° latitude South: many specimens of Andinentulus rapoporti (Condé, 1963) were sampled in the Reserva Forestal Coyhaique in Chilean Patagonia (E. Lanza & L. Galli unpub.)…”

“…We reviewed the available literature on Protura biogeography, outlining some general information about the distribution of the 77 genera known worldwide (Szeptycki, 2007;Galli et al, 2018;Shrubovych et al, 2020) within the Wallace's biogeographic regions. Moreover, based on cases from continental and insular fauna, we highlighted examples of species disjunct distributions for which both vicariance and dispersal events have been evoked.…”

“…Arctic species of Protura have mainly regionally restricted distributions or are known only from their type localities even though it must be kept in mind that sampling in these areas is limited to few sites. These small distributions and the morphological differences among some taxa, when compared to southern species, suggest a relict origin and a high level of endemism in arctic proturans (Shrubovych et al, 2020).…”

“…They stressed the importance of this area as biogeographical transition zone for soil microarthropods across Mediterranean, Pannonian, Alpine and Continental ecoregions. Finally, Shrubovych et al (2020) reviewed the proturans of the Arctic and found that species occurred outside the largest extent of ice-sheets during the last Pleistocene glaciation. Moreover, they highlighted that Verrucoentomon montanum (Martynova, 1970) and V. rafalskii Szeptycki, 1997, known from cool or mountainous areas of Central Asia, can be regarded as Pleistocene glacial relicts that were able to survive on refuges represented by non-glaciated mountaintops.…”

“…To date, nearly 800 species are known worldwide. The class comprises three orders, seven families and 77 genera (see Galli et al, 2018;Shrubovych et al, 2020). Very little is known about their autoecology, but it is undoubted that they have a low active dispersal capability.…”