Apphianus yuccae Beal, 2005

Beal, R. S., 2005, A New Genus and Species of the Tribe Attagenini (Coleoptera: Dermestidae) from the Mojave Desert of California, The Coleopterists Bulletin 59 (4), pp. 489-492 : 489-492

Apphianus yuccae Beal , new genus, new species

Description. General facies as illustrated ( Fig. 1 ). Integument of dorsal and ventral surfaces dark brown. Dorsal setae short, recumbent, golden brown except for large, subbasal area of short, golden, recumbent setae; some irregularly-spaced, suberect, golden setae present on posterior 1/2 of elytra, and long, golden, erect setae on lateral margins of pronotum and elytra; longest setae 0.38 mm in length; ventral surfaces densely covered with short, appressed, golden brown setae except on posterior lateral margins of abdominal sterna, where setae equal 1/2 length of segment. Head with frons nearly on same plane as dorsal surface of pronotum but fronto-clypeal region reflexed ventrad at about 908 angle at level of base of antennae Labrum emarginate. Eyes not prominent; eye not projecting strongly from side of head. Antenna with 7-segmented club (Fig. 3); terminal segment

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flat, leaflike. Median ocellus distinct. Scutellum visible, about 5/6 as long as antennal segment 10. Prosternum reduced; lateral process in front of front coxae about as wide as length of segment 4 of antenna; prosternal process narrow becoming razor-thin between front coxae. Front coxae prominent and nearly contiguous at apices. Coxal cavities open behind. Hind coxae not quite contiguous, not immovably fused to metasternum, terminating at lateral margin of metasternum and not meeting epimeron. Dorsal margins and apex of tibiae armed with short, stout spines; hind tibia also with fine setae about 5 3 length of spines (subequal in length to setae on margin of elytron). Abdomen with 5 externally visible sterna; visible sternum 1 divided by hind coxae (Fig. 4). Morphological sternum 8 thinly sclerotized, without modifications except for small apical emargination. Terga IX and X as illustrated (Fig. 4). Phallus (not figured) with bridge connecting lateral lobes not continuous at middle; base of aedeagus with short, broad apodemes.

Length from head to apex of elytra: 3.03 mm (length of pronotum and elytra combined: 2.97 mm); width across humeri: 1.58 mm.

Holotype male: Short Canyon, Kern Co., California, about 2 km west of junction of Highways 14 and 395, 3,300 feet elevation (35.718N, 117.908W), taken in antifreeze pitfall trap 30-iv-02 to 27-i-03 . Holotype deposited in collection of the California Academy of Sciences. Specimen has head and prothorax dissociated from meso- and metathorax with parts on separate points on same pin. The abdomen is dissected with parts mounted in balsam on slide .

Diagnosis. A character readily distinguishing this species from all other Dermestidae is the structure of the first visible abdominal sternum, which is divided externally by the hind coxae. It resembles Egidyella arcana in the shape of the head, in which the fronto-clypeal region is abruptly reflexed ventrad, in the seven-segmented antennal club of the male, in the reduced length of the prosternum in front of the procoxae, in the razor-thin shape of the prosternal process, and in having prominent front coxae. It is remarkably unlike Egidyella , which has seven visible abdominal sterna. The phallus is not figured, since its position on the slide distorts the proportions of the lateral lobes and aedeagus. Nevertheless, it differs from the phallus of Egidyella arcana , which has a thin but continuous rather than interrupted bridge connecting the lateral lobes on the ventral side and which has long, thin rather than short, relatively broad apodemes at the base of the aedeagus.

Etymology. Apphianus is a Greek, masculine patronymic honoring a Christian martyred in 306 A.D. under the reign of the Roman Emperor Maximinus; yuccae is the Latin genitive singular of Yucca , the genus of the plants beneath which the specimen was taken.

Discussion. It is quite unexpected to find a species of Dermestidae in which the first abdominal sternum is divided by the hind coxa, a characteristic of the Adephaga (except for the Gyrinidae ) and a character previously thought limited to the Adephaga. Is the first abdominal sternum in Apphianus truly divided? Externally it appears so, but the sternum continues beneath the coxae as a partially sclerotized membrane (Fig. 5). In Bembidion (Carabidae) there is no membrane beneath the coxae connecting the two sides of the first abdominal sternum ( Fig. 2 ). Whether this is true of all the Adephaga is not known. A divided first abdominal sternum is even more surprising in a species so similar in numerous other characters to Egidyella , and like Egidyella , occurring in a sandy habitat. Egidyella has a 7-segmented abdomen and has the first sternum entire. Whether the divided first abdominal sternum indicates that among the Polyphaga the Bostrichiformia are nearest the branch leading to the Adephaga, that the Dermestoidea are nearest to it among the Bostrichiformia, and that Apphianus is the most primitive of the Dermestoidea is a question needing further investigation. The divided first abdominal sternum in Apphianus could, of course, have arisen independently.

It is not known whether A. yuccae has an obligatory relationship to the Yucca plants beneath which it was taken. Seven other traps placed within one km of the same locality but not near Yucca plants yielded no further specimens of Apphianus . Neither did three other traps placed under clumps of Yucca but not left in place over the fall and winter months.

Intensive pitfall trapping in the same habitat and same general locality will doubtlessly yield additional specimens. I regret that for the present my health precludes such activity.

Figures

Fig. 1. Apphianus yuccae, dorsal aspect.

Fig. 2. Abdominal sterna of Bembidion sp. (Carabidae). Figs. 3–5. Structures of A. yuccae. 3) Male antenna; scale line ¼ 1 mm. 4) Male terga IX and X; scale line ¼ 0.02 mm. 5) Abdominal sterna.