Brachinus costipennis Motschulsky, 1859

Erwin, Terry L., 1965, A Revision Of Brachinus Of North America: Part I. The California Species (Coleoptera: Carabidae), The Coleopterists Bulletin 19 (1), pp. 1-19 : 4-6

Brachinus costipennis Motschulsky

Brachinus costipennis Motschulsky, 1859: 139 . Brachinus carinulatus Motschulsky, 1859 ; 139. ( NEW SYNONYMY) Brachinus glabripennis LeConte, 1858: 28 . ( NOMEN NUDUM)

In 1862 (p. 523) LeConte listed Brachinus lecontei Motschulsky as a synonym of B. costipennis , however Ponamarenko has compared the "type"

specimens of these species, and they are definitely different. For further details, see Brachinus fidelis LeConte.

TYPE LOCALITY: B. costipennis : " California "; B. carinulatus : " California ."

TYPE SPECIMENS: Two cotypes of B. costipennis and two cotypes of B. carinulatus are in the Motschulsky collection at the University of Moscow. One specimen of B. costipennis is in the LeConte collection, designated as type number 8329 , at the Museum of Comparative Zoology, Cambridge, Massachusetts. Dr. Darlington states that this specimen is very likely a cotype from Motschulsky, with whom LeConte is known to have corresponded .

DISTRIBUTION: This species is found in most of the southwestern United States and as far north as Tehama County in California. It is one of three species occurring on Santa Cruz Island, 20 miles off the coast of Santa Barbara County in southern California ( fig. 10 ).

DESCRIPTION: Size. Length 5 to 8 mm.; width 4 to 4.2 mm. Coloration. Elytra of both sexes bluish with blue epipleura; head and pronotum ferrugineus; mesal edges of mandibles piceous; antennal segments 1-3, legs, palpi, and venter ferruginotestaceous; antennal segments 4-11 dusky brown; mesepisterna and sides of abdominal sterna ferrugineus, rarely brown. Head. Labrum entire; dorsal surface of mentum concave, with a ring of setae surrounding concavity; bead around eyes entire except for a short area behind each antenna; furrows on frons very shallow and smooth; only a few setae at most behind eyes and on top of head; microsculpture consists of small isodiametric meshes. Pronotum. Widest at anterior third; anterior angles prominent and rounded; posterior angles prominent, acute and directed posteriorly, with lateral basal impressions shallow; lateral margins slightly reflexed and narrowly beaded with dark reddish brown; disc flat, sometimes slightly convex, barely rugose down midline and at most a few setiferous discal punctures; anterior transverse impressions deep; microsculpture consists of isodiametric meshes. Elytra. Male elytra truncate, widest just behind middle; moderately costate; microsculpture consists of small isodiametric meshes; glabrous except for regularly spaced hairs in 8th interval. Female elytra similar except proportionally wider than those of male. Aedeagus (fig. 1). Phallus strongly arched; ending in an apical knob; microsculpture lacking. Endophallus bears a poorly pigmented virga, consisting of a "V" shaped tip, with a median ventral fin. A pigmented intravirgal piece occurs at the base of this fin.

CALIFORNIA LOCALITY RECORDS: 397 specimens were examined. Alameda County: (Oakland Hills) CAS; Fresno County: (Sanger) CAS, (LeFerre Creek) CAS, (Camp Greeley) CAS; Humbolt County: (Garberville) CAS; Imperial County: (Carrizo) SDNHM, (Castiac) UIM; Los Angeles County: (San Francisquito Canyon) LACM, (Pasadena) LACM, (Camp Bonita, San Gabriel Mts.) LACM, (Big Dalton Dam) ATM, (Big Tujunga) LACM, (Los Angeles River) LACM, (Rio Hondo) LACM, (Frenchman Flats) LACM, (Lake Arrowhead) CAS, (Tujunga Pass) ATM; Madera County: (Coursegold) UIM CAS; Mendocino County: (Ukiah) VVB; Monterey County: (Stone Canyon) CAS; Orange County: (Costa Mesa) ATM; Placer County: (Placer County) CAS; Riverside County: (Simond's) LACM, (Palm Canyon) LACM, (Riverside) CAS, (Elsinore Lake) CAS, (Hemet) VVB, (Gilman Hot Springs) ATM; San Bernadino County: (Cajon Wash) LACM, (Colton) CAS, (Cajon Pass) ATM; San Diego County: (Mission Dam) SDNHM, (Mission Valley) SDNHM, (Pine Valley) SDNHM, (Dehesa) SDNHM, (El Monte Oaks) SDNHM, (San Diego) SDNHM, (Valley Center) SDNHM, (Warner's Ranch)

SDNHM, (Rincoln) SDNHM, (Banner) SDNHM, (Oceanside) CAS, (Poway) CAS, (Descanso) CAS; San Luis Obispo County: (Arroyo Grande) CAS; Santa Clara County: (Adobe Creek) CAS; Santa Cruz Island: (Santa Cruz Island) CAS; Sonoma County: (Duncan Mills) CAS; Tehama County: (hills west of Tehama County), CAS; Tulare County: (Sequoia Park) VVB; Ventura County: (Santa Paula) CAS; Yolo County: (Davis) ATM.

DERIVATION OF THE NAME: Latin, costa - rib; pennis wing; referring to the costate elytra.

DISCUSSION: This species is unique among the Brachinus in our fauna because of the concave mentum surrounded by setae. Also, this is the only California species whose members possess glabrous elytra. The male is further distinguishable by having the apical knob of the adeagus so well developed. The species is widely distributed within the state, as indicated by the collection records.

Figures

FIGURES 10-13, Brachinus spp. California distribution maps.