Dyschirius, BONELLI

Pollock, Darrena A. & Davidson, Robert L., 2015, DyschiriusBonelli (Coleoptera: Carabidae) at Lake Meredith, Texas: Habitat and Locality Information forDyschirius CriddleiFall, Range Extension forDyschirius larochelleiBousquet, and Notes on Other Species, The Coleopterists Bulletin 69 (4), pp. 736-738 : 736-738

DYSCHIRIUS BONELLI ( COLEOPTERA : CARABIDAE ) AT LAKE MEREDITH, TEXAS: HABITAT AND LOCALITY INFORMATION FOR DYSCHIRIUS CRIDDLEI FALL , RANGE EXTENSION FOR DYSCHIRIUS LAROCHELLEI BOUSQUET , AND NOTES ON OTHER SPECIES

DARREN A. POLLOCK Department of Biology , Eastern New Mexico University Portales, NM 88130, U.S.A. [e-mail]

AND

ROBERT L. DAVIDSON Section of Invertebrate Zoology , Carnegie Museum of Natural History Pittsburgh, PA 15213, U.S.A. [e-mail]

The carabid genus Dyschirius Bonelli comprises 60 Nearctic species ( Bousquet 2012), most of which are burrowers along sparsely vegetated shorelines ( Lindroth 1961). One of the most distinctive species is Dyschirius criddlei Fall. For the most part, the large size alone (5.5–7.5 mm) will distinguish it from other Nearctic Dyschirius species , except Dyschirius edentulus Putzeys (metallic black; reddish brown and unmetallic in D. criddlei ). The following diagnostic combination will clinch identification: no microsculpture, no basal margin on elytra, one subhumeral fovea, one discal elytral puncture and seta, large size, reddish brown, unmetallic. From its description by Fall (1925) until Lindroth (1961), the only known locality for this beetle was the type locality of Baldur, Manitoba, Canada. Larson (1968) extended the distribution: “… criddlei has been collected from saline or alkaline localities from New Mexico, Kansas, and southern Manitoba ”. The most recent distribution of D. criddlei was given by Bousquet (2012): Manitoba, Florida (Monroe Co.), Kansas (Stafford Co.), North Dakota (Grand Forks Co.), Nebraska (southeastern, but no county specified), New Mexico (Chaves Co.), and Texas (Hutchinson Co.). The Texas record was based on our records but without detailed locality or habitat information. The purpose of this note is to provide additional information about this new Texas locality for D. criddlei , including other Dyschirius co-inhabitants, and to document a significant inland range extension for Dyschirius larochellei Bousquet.

The Dyschirius beach is along the east shore of a small lake separated by an elevated area and Hwy 687 from the main body of Lake Meredith. The actual locality is TX, Hutchinson Co., Lake Meredith National Recreation Area, Spring Canyon, 35.717457°, -101.549340°, elevation 2,820 ft. (860 m). The shoreline substrate was clay-sand with very sparse vegetation, primarily grasses ( Fig. 1 ). The lake water was not obviously saline (by taste), but the beach substrate did have a definite “salt crust”, especially farther from the waterline, possibly indicating salinity, at least in the substrate. This area is open to the public, and the beach area is reasonably heavily disturbed by swimmers. Daytime sampling was done on six occasions during May 2011 through April 2013. Specimens were collected after splashing the shoreline (to a maximum of approximately 6 m from the water’ s edge) with lake water. Specimens of Dyschirius were thereby forced to the surface and collected.

Surprisingly, in addition to the multiple D. criddlei specimens and the one individual of D. larochellei (see below) taken from the Spring Canyon site, five additional species were represented among the collected Dyschirius specimens. To us, this was astonishing, as in our experience two or three Dyschirius species in one habitat is not unusual, but seven at one site and all in the same ecological zone seems exceptional. Equally interesting, these represent a surprisingly broad mixture of biogeographical affinities (distributions from Bousquet 2012): Dyschirius aratus LeConte and Dyschirius interior Fall (western US and Canada); Dyschirius sellatus LeConte (eastern US and Canada); Dyschirius campicola Lindroth (interior of US and Canada, not reaching either coast); and Dyschirius sphaericollis (Say) (transcontinental in US and Canada). Perhaps the geographical location is a crossroad of biogeographical zones, and perhaps the relative paucity of water forces strange bedfellows to share habitat.

The following are the dates of collection at the site and the species present (species indicated as “common” were represented by> 5 specimens): 20 May 2011: D. interior , D. sphaericollis ; 27 May 2011: D. aratus (common), D. campicola , D. criddlei , D. sellatus , D. interior , D. sphaericollis ; 18 July 2011: D. aratus (common), D. criddlei , D. larochellei (the only specimen from any collecting date); 9 August 2011: D. aratus (common), D. criddlei ; 16 May 2012: D. aratus , D. campicola , D. criddlei , D. sphaericollis ; 21 April 2013: D. interior . Other carabids in the same habitat included several species of Bembidion Latreille , Elaphropus Motschulsky , and the pale form of Omophron robustum Horn (the unmarked form described as Omophron decoloratum Fall ). Also, as is usual for Dyschirius , there were several species of Bledius Leach (Staphylinidae) present. Specimens examined for this study are deposited in the collections of the Carnegie Museum of Natural History, and Eastern New Mexico University (Department of Biology).

Bousquet (1988) described D. larochellei from specimens collected along the US Gulf Coast and also the northeastern coastal regions of the US. The only Texas record mentioned is coastal, from Aransas Co. ( Goose Island State Park : 28°8′1″N, 96°59′3.5″W). The new record from Hutchinson Co. represents an inland distance of ca. 1,038 km from the only other Texas record for the species. Larochelle and Larivière (2003) describe the habitat as “coastal lowlands…sea beaches; borders of salt marshes and lagoons,” so this will have to be modified if indeed the species is resident in Hutchinson Co. and not merely a stray .

Figures

Figs. 1–2. 1) The “Dyschirius beach” at Spring Canyon, Lake Meredith Recreation Area, TX, looking north (photograph taken 9 August 2011). Dyschirius criddlei was found primarily within the bare patch in the fore- to mid-ground; 2) Distribution of D. criddlei in North America and Dyschirius larochellei in Texas. Localities in the USA are indicated by county only; square in Canada represents type locality of D. criddlei in southern Manitoba. The Nebraska locality (as mentioned by Bousquet 2012) is indicated by a question mark, as the county is unknown. The circle indicates the previously known Texas locality for D. larochellei (Aransas Co.).