Deretaphrus gracilis Blackburn, 1903

Lord, Nathan P. & McHugh, Joseph V., 2013, A Taxonomic Revision of the Genus Deretaphrus Newman, 1842 (Coleoptera: Cucujoidea: Bothrideridae), The Coleopterists Bulletin (mo 12) 67, pp. 1-107 : 29-30

Deretaphrus gracilis Blackburn, 1903

( Figs. 66 , 100–101 , 149 , 167 , 174 , 206–207 )

Deretaphrus gracilis Blackburn, 1903: 124 . Carter and Zeck 1937: 200–201.

Diagnosis. This species can be readily distinguished from congeners by the slightly convex pronotal disc with moderately sparse, small punctures and a sharply impressed pronotal median longitudinal canal, the simple abdominal ventrite V, the shape of the submentum, a distribution restricted to Western Australia, and genitalic characters. This species is most similar to D. piceus and D. iridescens . Deretaphrus gracilis can be distinguished from D. piceus by the simple abdominal ventrite V (without two depressions on either side of midline), the larger and denser punctures on the pronotal disc, the less foveate anterior portion of the pronotal median longitudinal canal, and the less dense setation of the antennal club. It can be distinguished from D. iridescens by having more strongly impressed anterior and posterior portions of the median longitudinal canal, a pronotum that is slightly depressed medially and deflexed laterally, and a distribution restricted to Western Australia.

Redescription. Length 5.2–9.9 mm. Width 1.5–2.7 mm. Body elongate, parallel, red; dorsal surface glabrous, matte to weakly shiny; ventral surface moderately shiny, glabrous except for minute setae that arise from punctures. Head: In dorsal view, slightly narrowed anteriorly; without laterally expanded supra-ocular ridges; eyes visible from above; punctures small and dense except sparse along posterior margin. Frontoclypeal suture distinct, arcuate anteromedially. Anterior margin of clypeus broadly arcuate. Submentum shape as in Fig. 51 ; distinctly separated from subgenal braces, with paired setose pits; anterior margin moderately expanded anteroventrally over oral cavity; palpi and a portion of the mentum visible. Antennal groove well-developed, impunctate. Antenna densely setose; segment 1 with few setae on ventral surface; segments 2–8 with a single transverse row of moderately long setae, setae greater than half the length of the segment from which they arise; antennal club segments with 2 transverse rows of setae, 1 row located medially, with short setae, second row at apical margin of segments, with long setae. Antennal club subsymmetrical. Dorsal surface (external face) of mandible with median setose groove. Thorax ( Fig. 66 ): Pronotum elongate, widest near anterior ¼; dorsal surface flat, slightly impressed along midline; anterior angles rounded, not distinctly pronounced; anterior margin arcuate medially, slightly wider than head; base narrower than elytral bases; posterior margin slightly sinuate; posterior angles with small denticle; lateral margin with incomplete carina, forming a subtle raised border in dorsal view. Pronotal disc with small, sparse punctures. Pronotal median longitudinal canal present, strongly developed, interrupted anteriorly; anterior portion a weak slit, the surrounding area slightly depressed, more densely punctate; raised interruption of the canal impunctate; posterior canal narrow, strongly impressed, internal lateral margins of canal grooved, slightly tapering posteriorly, open at the base. Hypomeron minutely punctate; lateral walls nearly vertical. Prosternum flat medially, strongly deflexed at lateral margin. Tergosternal suture slightly sinuate. Elytra ( Figs. 100–101 ): Elytron flattened dorsally; interstitial intervals 3, 5, and 7 feebly raised near apex. Basal elytral margin with intervals 3 and 5 each ending in a knob-like protuberance; protuberance of interval 5 narrowly separated from or narrowly joining finger-like callosity on the elytral shoulder. Legs: Setation sparse; inner face of tibia with double fringe of long, dense setae. Tarsus sparsely setose except for 2 pockets of dense setae on the ventral surface at the apex of tarsomeres 1–3. Abdomen: Ventrite V simple. Aedeagus: Phallobase as in Fig. 149 . Tegmen consisting of paired, elongate, anteriorly projecting, subtriangular plates at middle; plates narrowly touching medially. Basal piece with long anterolateral struts; struts recurved anteriorly. Parameres rounded, broadly fused to one another near base, collectively slightly transverse and articu- lated to phallobase; each paramere with a pair of oblique, elongate-oval patches near middle and a pair of subcircular patches near apicolateral margin, patches lighter in color than remainder of paramere; paramere sparsely setose with short setae at apical margin; dorsal surface of paramere lacking process; Penis as in Fig. 167 ; elongate, slender, variously curved; apex narrowed and pointed; base slightly expanded, bearing long, slender, paired anterior struts. Penis slightly lighter in color near base.

Variation. The color is variable within the species, ranging from light reddish brown to nearly black. The depth of the posterior portion of the pronotal longitudinal canal is shallower in smaller individuals and deeper in larger individuals.

Distribution. Known only from Western Australia ( Fig. 174 ).

Biology. Not known.

Remarks. Blackburn (1903) did not mention the number of specimens examined. In order to stabilize this name, a lectotype is here designated from the syntype series of D. gracilis .

Type Locality. Western Australia .

Type Material Examined. L E C T O T Y P E ( Figs. 206–207 ) ( BMNH, point-mounted) label data: “T. 7200 W.A. [in Blackburn’ s hand at base of card-mount, “7200” and “W.A.” are written in red ink, “T.” is written in black ink] // Type H.T. [round label with orange border] // Australia. [red underline] Blackburn Coll. B.M. 1910-236. // Deretaphrus gracilis, Blackb [in Blackburn’ s hand]” [ BMNH 100 NL, examined]. Sex not determined. This type was removed from the original card-mount and point-mounted. The original card-mount and abdomen (glued to a card) are pinned beneath the specimen. Upon dissection, the genitalia were not found. It is possible a previous worker dissected the genitalia and did not place with the specimen.

Additional Material Examined (12). AUSTRALIA: WESTERN AUSTRALIA: 7 mi. E by N of Balladonia HS ( ANIC 170 NL); Boorabbin ( MNHUB 3 NL); Coolgardie ( BMNH 92 NL); Eradu ( ANIC 32 NL); Mundaring ( BMNH 82 NL); Porongurup National Park ( WAMP 63 NL); Swan River ( ANIC 307–308 NL, OUMNH 9 NL, SAMA 72 NL); Wurarga, Marloo Station ( ANIC 159 NL); STATE UNKNOWN: no locality ( OUMNH 20 NL).

Figures

Figs. 66–74. Deretaphrus species, pronotum. 66) D. gracilis; 67) D. hoplites; 68) D. ignarus; 69) D. incultus;

Figs. 100–105. Deretaphrus species, elytra, dorsal and lateral views. 100–101) D. gracilis; 102–103) D. hoplites;

Figs. 149–157. Deretaphrus species, phallobase. 149) D. gracilis; 150) D. hoplites; 151) D. ignarus; 152) D. incultus;

Figs. 165–172. Deretaphrus species, penis (left: dorsal view; right: lateral view; phallobase, to scale with penis). 165) D. boliviensis; 166) D. bucculentus; 167) D. gracilis; 168) D. hoplites; 169) D. ignarus; 170) D. oregonensis; 171) D. parviceps; 172) D. puncticollis.

Figs. 173–174. Distribution of Deretaphrus species. 173) D. alveolatus, D. antennatus, D. parviceps, and D. rodmani;

Figs. 201–209. Primary type specimens and specimen labels of Deretaphrus species. 201) Presumed pin and label of the original type of D. fossus, BMNH; 202–203) D. fossus, neotype, SAMA; 204–205) D. cordicollis, lectotype, BMNH; 206–207) D. gracilis, lectotype, BMNH; 208–209) D. hoplites, holotype, SAMA.

Figs. 48–53. Deretaphrus species, head capsule, ventral view, showing setae and shape of submentum. 48) D. ignarus;