Epitragosoma arenaria Brown and Triplehorn

Brown, Kirby W. & Triplehorn, Charles A., 2001, EPITRAGOSOMA ARENARIA, A New Genus and Species from Texas (Coleoptera: Tenebrionidae), The Coleopterists Bulletin 55 (4), pp. 515-521 : 519-521

Epitragosoma arenaria Brown and Triplehorn , new species

Figs. 1–8

Description. Female ( Fig. 1 ). Moderately shining reddish­brown with an aeneous tinge, clothed with short, fine but conspicuous, appressed, grayish­silver pubescence. Head: ( Fig. 5 ) slightly broader than long; temporal area scarcely swollen behind eyes, much less than one half the length of longitudinal diameter of eye; head surface coarsely and densely punctured, each puncture with a conspicuous appressed seta. Pronotum: slightly broader than long, about equally wide at middle and at hind angles; lateral margins distinctly sinuate in basal one third with basal angles notably everted and apical angles not to slightly everted; surface coarsely and densely punctured, each puncture with a prominent, appresed seta, setae of anterior portion of disc directed caudad, lateral setae directed mediad, forming a swirling dendritic effect over much of pronotum with a faint impunctate medial line. Elytra: surface finely and shallowly but densely punctured with a fine pattern of microreticulations between punctures; each puncture with a conspicuous, appressed seta directed caudad (setae somewhat shorter and finer than those of head and pronotum); faint dark subcutaneous longitudinal lines are visible but pattern of punctures is random. Ventral surface: of pronotum coarsely and rugosely punctured; punctures progressively less dense on prosternum and prosternal process, each puncture with an appressed seta similar to pronotum; metasternum with large, shallow, contiguous punctures; abdominal sterna finely and rugosely punctured, clothed with appressed setae that are similar in size but less conspicuous than those of elytra. Legs: densely punctured, each puncture bearing an appressed grayish­silver seta; femora smooth; tibae rugose, bearing numerous ventral and latero­ventral stout orange spines especially towards apices; tarsi with dorsal and lateral surfaces similar to tibiae with coarse, stout setae confined to apices and ventro­apical surfaces of pre­apical segments except for metatarsus ( Fig. 7 ) with a more general ventral distribution of stout setae; all apical tarsal segments with two regular vetral rows of stout setae. Abdominal tergum: 7 ( Fig. 2 ) with two prolonged sharp projections; tergum 8 trapezoidal and with an apico­central uplifted spatulate structure. Male: Similar to female but slightly smaller and more slender. Abdominal tergum 7 weakly bifurcate; tergum 8 normal lunate ( Fig. 3 ).

Etymology. The name of this species refers to its sand dune habitat.

Type locality. U.S.A., Texas, Ward County, Monahans Sand Hills State Park , 16 July 1972, C. A., W. E. and B. W. Triplehorn.

HOLOTYPE. Female. Length 9.6 mm, width 4.5 mm.

Allotype. Male, same data as Holotype. Length 9.3 mm, width 4.2 mm.

Paratypes. All from same locality as Holotype: (110) same data as Holotype ; (1) same collectors as Holotype except 8 July 1968 ; (23) same collectors as Holotype except 28 July 1973 ; (10) 12 Sept. 1970 A. S. Menke ; (9) 3 Aug. 1963, J. G. and B. L. Rozen ; (50) 31 Aug.–1 Sept. 1982, Rolf L. Aalbu ; (32) 30 Sept. 1986, J. T. & E. A. Doyen ; (1) 2 Aug. 1987 (night sweep), C. B. Barr ; (1) 19 July 1977, A. V. Evans ; (1) 13–14 Sept. 1959, E. R. Tinkham ; (16) 21–22 Aug. 1982, R. Turnbow ; (1) 6 July 1978, R. Turnbow ; (6) 23 July 1976 (sweeping grass), G. H. Nelson ; (10) 15–16 July 1975 (sweeping grass), G. H. Nelson ; (12) 21 July 1972, Karl Stephan. Measurements: Length: 9.1– 10.7 mm; width: 4.0– 4.9 mm. Holotype, Allotype and Paratypes are deposited in the United States National Museum. Additional Paratypes are deposited in the Ohio State University Museum of Biological Diversity; Peabody Museum of Natural History, Yale University ; Museum of Comparative Zoology, Harvard University; American Museum of Natural History ; University of California, Berkeley and Davis; Texas Tech University, Lubbock, Texas; Florida A & M University, Tallahassee , Florida; Florida State Collection of Arthropods , Gainesville; California Academy of Sciences; British Museum (Natural History); Kirby W. Brown Collection, Paradise , California; G. H. Nelson Collection, Kansas City, Missouri; R. Turnbow Collection, Fort Rucker , Alabama; C. B, Barr Collection, Berkeley , California, and Rolf L. Aalbu Collection, Sacramento , California.

Other Specimens. TEXAS, Culberson County: (1) 5 miles east of Van Horn, 12 Sept. 1970, A. S. Menke. Reeves County: (4) Pecos, 23 Sept. 1938, D. J. and J. N. Knull. Winkler County: (91) 4 miles northeast of Kermit, 25 August 1971 (on tassels of tall grass), K. W. Brown, C. O’Brien and P. Petrulis; (25) 11 miles northeast of Kermit, 12 Sept. 1971 (on tassels of tall grass), K. W. Brown, (1) 10 miles northeast of Kermit on Hwy 115, 3,200′, 12 Sept. 1971, K. W. Brown. NEW MEXICO, Chaves County: (10) Mescalero Sands, Caprock, 9 July 1954, Cazier and Gertsch; (3) Mescalero Sands, 45 miles east of Roswell, 12–13 Sept. 1959, E. R. Tinkham. Lea County: (8) 4 miles north of Maljamar, 1 Sept. 1962 (on Helianthus ), H. V. Weems, Jr.

Habitat. Most of the large series taken by us in Ward and Winkler Counties, Texas, were found head down in the leaf axils of dune­stabilizing grasses. Specimens of this grass from Monahans were determined as Panicum havardii Vasey by Dr. David Keil. This is apparently a native grass in arroyos and sand hills of western Texas, southern New Mexico and northern Mexico (Hitchcock 1935). A few specimens were taken on the sand around clumps of grass and one was found on a sunflower head.

Comparison. Other than the superficial resemblance to Epitragopsis species discussed in the generic comparison, this species is most closely approached by Lobometopon ovale (Casey) found in eastern Texas (Triplehorn 1980). Besides characters already discussed at the generic level, L. ovale is less densely hirsute, posterior prothoracic angles not or only very weakly everted, and body slightly more robust. Furthermore L. ovale is associated with the dicotyledon plant Eriogonum multiflorum (Polygonaceae) , while E. arenaria is associated with a monocotyledon grass (Graminae).

Variation. Three large series are on hand from rather close locations; (1) Monahans Sand Hills State Park, (2) 4 miles northeast of Kermit, and (3) 11 miles northeast of Kermit. Kermit is approximately 20 miles northwest of Monahans Sand Hills. When placed side by side, series of each population are recognizably distinct. Most notable are size differences (the Monahans specimens are larger than the Kermit specimens) but also there are subtle morphological differences. This is apparently a case of microgeographic variation similar to Coelus ciliatus (Doyen and Slobodchikoff 1984) . Because of this variability we have restricted the type series to those specimens collected only at the type locality.

Sexual Dimorphism. Other than the structure of abdominal tergites 7 and 8, there appears to be little sexual dimorphism in this species. There is a weak tendency to a slightly smaller and narrower body in males.

Figures

Fig. 1. Epitragosoma arenaria dorsal habitus, female.

Figs. 2–3. Epitragosoma arenaria. 2) apical abdominal tergites, female; 3) apical abdominal tergites, male.

Figs. 4–8. Epitragosoma arenaria. 4) prosternal process, ventral view; 5) head, dorsal; 6) antenna; 7) metatarsus; 8) metathoracic wing.