Craniotus pubescens LeConte, 1851

Aalbu, Rolf L., Smith, Aaron D. & Piñero, Francisco Sanchez, 2015, A Revision of Craniotus Leconte (Coleoptera: Tenebrionidae: Pimeliinae: Asidini), with Descriptions of New Insular Species from Mexico and Notes on Distribution and Biology, The Coleopterists Bulletin (mo 14) 69, pp. 93-100 : 96-100

Craniotus pubescens LeConte, 1851

( Figs. 5–13 )

Craniotus pubescens LeConte 1851: 142 . Craniotus blaisdelli Tanner 1963: 169 . New

synonymy.

Diagnosis. Craniotus pubescens can be easily separated from other Craniotus species by the less globose pronotum with lateral margins not bearing lateral projections.

Material Examined. (443 from the following 191collectingevents). CALIFORNIA(260specimens / 122 collecting events):IMPERIAL CO: Anza Borrego narrows (1); El Centro (1); La Puerta (2); Calexico, 20 mi. W (1); Myer Valley (2); Ocotillo (3); Palo Verde, 10 mi. W., Coon Hollow (1); Salton City (7); Signal Mt., (6); Westmoreland (1); INYO CO. Eureka Valley (4); Keeler, 1 mi. W (1); Saline range (4); Scotty’ s Castle, 15.5 mi. NW (10; Upper Shoshone Cave (1);KERN CO; Mojave (1);ORANGE CO; Huntington Beach (1); RIVERSIDE CO. 1000 Palms, 4 mi. E (2); Andreas Cyn. (2); Anza-Borrego St. P.Oyster Cyn.,(1); Blythe (3); Borrego (2); Caliente, Cyn W of (3); Cathedral City (1); Conejo Well ( JTNM) (1); Deep Canyon, N gate, (3); Joshua Tree National Monument ( JTNM), Squaw Tank,. 7 mi S (10); Painted Cyn., (4); Palm Desert 3); Palm Springs (35); Pinto Basin (1); Pinto Wsh. Well ( JTNM) (5); Pinyon Wells ( JTNM) (4); Pleasant Valley 2 ( JTNM) (6); Pleasant Valley 3 ( JTNM) (3); Quail Guzzler ( JTNM) (1); Queen Valley ( JTNM) (1); Riverside (4); Salton Sea (1), State Park (1); Santa Rosa Mts. , Agua Alta cyn., (4); Whitewater Cyn. (1), 2 mi. N Hwy 60 (1), 1/ 2 mi. N 60 (4); Yaqui Flats (1); SAN BERNARDINO CO; 29 Palms (1); Amboy Crater (1); Bonanza King Mine (1); Deadman Pt. (4); Lucerne Valley , 14 mi. E (2); Morongo Valley (6); Needles (4); Ord Mts , (1); Pisgah Crater (1); Zzyzx , 1 mi. S (1); SAN DIEGO CO; Anzá- Borrego State Park , (1); Coyote (2); Borrego (1); Borrego Valley (1); La Puerta (4); Mason Valley (66); San Diego (5); Yaqui Flat (1). ARIZONA (52 specimens / 10 collecting events): YUMÁ CO; Dateland , on dunes (20); Gila Mts. , (29); Yuma , Hwy . 95, 10 mi. N (1); PINAL CO; Casa Grande , 30 mi. W (1); MOJAVE CO; GoldRoad (1). NEVADA (75 specimens / 32 collecting events): CLARK CO. Valley of Fire (1); NYE CO; Amargosa Valley (1); Mercury (4); Rock Valley (69). MEXICO, BAJA CALIFORNIA (133 specimens /13 collecting events); Bahia San Luis Gonzaga , 15 mi. SW (2); Isla Partida (2); Sierra San Pedro Martir , Canyon del Cabana (3); El Cajon (1); San Felipe (2), 31 mi. N (5); Gas Kills Tank (1); Bahia de Los Angeles (10), Cardonal , 6 mi. S. (2); Isla Sal Si Puedes (3); Rancho Santa Inez , 6 mi. NW (11), 9 km NW (7); San Telmo (1) Mainland near Isla Pescadero (5) .

Variation. Ta n n e r (1 9 6 3) d i s t i n g u i s h e d C. blaisdelli from C. pubescens by the following characters: 1) large size; 2) elytral surface consisting of “sparse, short black setae, devoid of striae and with a more or less dull luster yet with a shining surface” rather than having “three rather distinct lines of areas of either side of the suture which are covered with brownish decumbent thickly placed setae” separated by small places devoid of setae; and 3) prothorax “more round and convex with numerous deep punctures”. The type and paratypes of C. blaisdelli , as well other specimens from the same locality, were examined. As we could not find any consistent morphological differences, including in the genitalia, we believe that these characters, including the size of the specimens and the relative inflation of the prothorax which are variable within populations, are the results of a north-south clinal variation. These more or less form two populations: the southern population, corresponding more or less to the type of C. pubescens and the northern population corresponding to “ blaisdelli ”, which seems to occur only in a few localities, mainly Eureka Valley, Inyo Co., California and Rock Valley, Nye Co., Nevada (see Tanner 1963). Northern population specimens have a papillose-punctate pronotum which tends to be more sparsely furnished with recumbent, yellow setae. The pronotum tends to be less inflated as well, resulting in lateral margins which are less rounded, although this character is variable. The elytra in these specimens have very few recumbent, yellow setae, resulting in a more or less glabrous elytral surface. Because of this, less debris tends to accumulate in the more depressed strial areas.

Distribution. Craniotus pubescens ranges from Inyo County (California) and Nye County (Nevada) to the state of Baja California, Mexico ( Fig. 13 ). Interestingly, C. pubescens also occurs on Isla Partida as well as Isla Sal Si Puedes, islands in the central western part of the Gulf of California and between the areas where the two new species occur. As these islands are separated from the larger Isla Angel de la Guarda by only a few hundred meters of ocean depth and Isla Angel de la Guarda was separated from the mainland of Baja California only fairly recently, populations from the north may have moved south along this bridge during glacial maxima, when ocean levels were higher. Elevational range is fairly low: from 0 to 750 m. It has been collected by a number of techniques: ground trap, pitfall trap, blacklight, under board, under cow dung, under rock, and under agave ( Agave deserti Engelm. , Asparagaceae ).

KEY TO THE KNOWN ADULTS OF THE

GENUS CRANIOTUS

1. Lateral margins of pronotum bearing lateral connate projections longer anteriorly,

each bearing moderately long, erect seta ( Figs. 1–4 )................................................ 2

1′. Lateral margins of pronotum without lateral connate projections ( Figs. 5–12 ) ................... ...................... Craniotus pubescens LeConte

2. Lateral margins of pronotum strongly serrate with more than 6 lateral connate projections. Elytral punctures very large, set in uneven striae ( Figs. 1–2 ) ............................................ ....... Craniotus mardecortesi Aalbu, Smith, and Sanchez Piñero , new species

2′. Lateral margins of pronotum with 6 or fewer connate projections. Elytral surface with punctures fine, scattered unevenly ( Figs. 3–4 )....... ............ Craniotus triplehorni Aalbu, Smith, and Sanchez Piñero , new species

Figures

Figs. 5–8. Dorsal habitus of Craniotus pubescens from four populations. 5) Male, Nevada, Nye Co., Nevada test site; 6) Male, Arizona, Yuma Co., I-8 rest stop on east side of Mohawk Mts.; 7) Female, California, Joshua Tree National Monument, Pleasant Valley; 8) Male, Arizona, Maricopa Co., north side of Saddle Mtn., west of Tonopah.

Figs. 9–12. Lateral habitus of Craniotus pubescens from four populations. 9) Male, Nevada, Nye Co., Nevada test site; 10) Male, Arizona, Yuma Co., I-8 rest stop on east side of Mohawk Mts.; 11) Female, California, Joshua Tree National Monument, Pleasant Valley; 12) Male, Arizona, Maricopa Co., north side of Saddle Mtn., west of Tonopah.

Fig. 13. Craniotus species, distribution map. Blue pentagrams = C. mardecortesi. Green circles = C. triplehorni. Red triangles = C. pubescens.

Figs. 1–2. Craniotus mardecortesi, Holotype female, habitus. 1) Dorsal view; 2) Lateral view.

Figs. 3–4. Craniotus triplehorni, Holotype female, habitus. 3) Dorsal view; 4) Lateral view.