Arianops clintoni, Carlton, 2008

Carlton, Christopher E., 2008, Eight New Species ofArianopsBrendel from the Southeastern United States with an Updated Key and Notes on Additional Species (Coleoptera: Staphylinidae: Pselaphinae), The Coleopterists Bulletin 62 (2), pp. 297-323 : 297-323

Arianops clintoni , new species

( Figs. 5–6 , 21–23 , 35 )

Holotype male ( Figs. 5–6 ). / USA, AL, Monroe Co. 1 mi. S Claiborne Dam. 31 ° 35 9 30 0 N 87 ° 32 9 12 0 W/ Berlese. Cypress Loop Trail. 31 May 1995. CE Carlton / W.H. Cross Expedition / Arianops clintoni Carlton, 2007 Holotype male/. Type deposition, Field Museum of Natural History, Chicago, IL .

Etymology. This species is named in honor of Bill Clinton, Arkansas native, 42nd President of the United States of America, and promoter of humanitarian causes.

Description. Holotype male. Measurements (in mm): head 0.50 long, 0.50 wide; pronotum 0.55 long, 0.50 wide; elytra 0.70 long, 0.80 wide; median lengths of visible abdominal tergites 1–5, respectively 0.35, 0.08, 0.07, 0.45, 0.10. Antennomeres 1–11, respectively 0.13, 0.12, 0.10, 0.07, 0.10, 0.06, 0.07, 0.06, 0.08, 0.10, 0.20. Aedeagus 0.45 long, 0.30 wide. Total length 2.70.

Head ( Fig. 21 ). Lateral vertexal carinae moderate, gradually weakening posteriorly, obsolete at a point even with vertexal foveae. Median occipital carina weak, barely from just anterior to vertexal foveae to posterior margin of occiput. Vertexal foveae nude, connected via weak u-shaped depression that is expanded anteriorly, broadly concave between antennal tubercles. Carinae to antennal tubercles barely extending onto clypeus; clypeus not carinate medially. Labral margin bearing small median and lateral teeth. Lateral carinae from clypeus to ocular spines well-developed. Ocular spine small, blunt, oriented laterally. Mentum not toothed.

Pronotum. Basomedian fovea, submedian spines and bumps absent. One pair of small submedian foveae present. Two pairs of basolateral foveae present, one 308 pair on lateral aspect of pronotum, nearly vertical in position, another more posterior and medial, located just lateral to submedial foveae. Pronotum weakly transversely rugose along basal margin.

Elytra. Basal margin of each elytron weakly arcuate posteriorly across base of elytral disc, weakly angulate at humeral declivity. Basal depressions and foveae absent.

Legs. Unmodified ( Fig. 22 ).

Abdomen. Dorsally weakly convex, almost flat in median one-third, evenly declivous at tergite 4. Visible ventrite 4 with a short, stout, median, submarginal spine ( Fig. 23 ). Ventrite 5 broadly concave.

Aedeagus ( Fig. 35 ). Apical shelf broad, asymmetrical, with a deep rounded emargination, right portion broadly triangular, left narrowly triangular and bearing a row of three short setae, medial surface bearing a group of six fine setae. Right lateral wall of phallobase externally expanded to a broad lobe. Narrow, arcuate process extending from phallobase, paralleling the left shelf margin and surpassing its apex, simply acute to apex.

Female. Unknown.

Material examined. Only the holotype is known.

Distribution. The species is only known from the type locality in Monroe County, Alabama.

Comments. External characters of A. clintoni are consistent with Barr’s (1974) henroti species group, but not unequivocally. The flattened abdominal profile and absence of a median pronotal fovea support the placement, but the first character is gradational, and the second is not unique to this group. The general outline of the aedeagal ventral shelf is similar to that found in several other species within the group. From all other members of the henroti group it differs in possessing an elongate, arcuate process emerging from the interior of the aedeagal phallobase, presumably a component of the internal sac. The elongate left lateral process of A. teyahalee , also of the henroti group, was described as articulating with the left wall of the phallobase and bears a cluster of apical spinose processes. Processes of various configurations emerge from the phallobase interiors of other species, but they all differ substantially in being much shorter, or occurring in combination with other characters not found in A. clintoni . The broad lobe extending from the right lateral wall of the phallobase of this species is unique within the genus.

This species and A. obrieni are the only species of the genus known to occur outside the southern Appalachian or Ouachita Mountains . The type locality is in an area known as the Red Hills that encompasses parts of five counties in southwestern Alabama. Substrates are derived from silty claystone of the Tallahatta Formation, and the terrain is dissected by rolling hills and steep ravines where deep crevices form during weathering. The Tallahatta was formed from marine sediments during the Eocene and the area was unavailable for terrestrial colonization prior to the Miocene (Laws and Thayer 1992), so the existence of this species in the area is geologically recent compared with other species inhabiting geologically ancient mountains .

The type locality of A. clintoni is also the type locality of an anilline ground beetle, Anillinus folkertsi Sokolov and Carlton ( Sokolov et al. 2004). Specimens of both species were collected in the same litter sample from a riparian beech/ magnolia forest a short distance from the banks of the Alabama River. Attempts to collect additional specimens have thus far been unsuccessful. Barr (1974) noted the importance of river systems in the southern Appalachians as barriers that may have affected isolation and subsequent diversification of Arianops species. The importance of rivers as dispersal mechanisms for transporting founder populations from upstream sources should also be considered. The occurrence of members of both of these genera on geologically recent terrains of the Gulf Coastal Plain is probably the result of such dispersal. The location of the type locality in proximity to a major river having headwaters in the Appalachian foothills is consistent with this explanation.

As an interesting side note, a genus and species of salamander, Phaeognathus hubrichti Highton (1961) is also endemic to the Red Hills, though not known at this locality. It is the official state amphibian of Alabama and the first amphibian in the U.S. to receive protection under the U. S. Endangered Species Act (http:// www.archives.state.al.us/emblems/st_amphib.html). The type locality of the primitive gyrinid beetle Spanglergyrus albiventris Folkerts (1979) is also nearby, though the species is not endemic to the area.

Cavernensis species group

Figures

Figs. 5–8. Dorsal and lateral views, Arianops new species holotypes. 5–6) A. clintoni; 7–

Figs. 17–27. Arianops new species. 17) A. obrieni, head; 18) A. obrieni, female ventrites 5–6; 19) A. carteri, head; 20) A. carteri, mesothoracic coxa-femur; 21) A. clintoni, head; 22) A. clintoni, mesothoracic coxa-femur; 23) A. clintoni, ventrites 3–4; 24) A. ashei, head; 25) A. ashei, ventrites 3–4; 26) A. barri, head; 27) A. barri, ventrites 3–4.

Figs. 34–41. Arianops new species aedeagi, dorsal views. 34) A. carteri; 35) A. clintoni;