Ceratochodaeus darlingi Huchet, 2019

Huchet, Jean-Bernard, 2019, New data on the taxonomy and distribution of Philippine Ochodaeidae and description of a new species from Central Visayas (Coleoptera: Scarabaeoidea), Insecta Mundi 722 (722), pp. 1-10 : 3-6

Ceratochodaeus darlingi Huchet , new species ( Fig. 1–9 )

Type material. Holotype male ( ROM), labeled: a) “ PHILIPPINES, Negros Oriental / Cuernos de Negros , 7 km W / Valencia. 14-16 May 1987 / DC Darling / E Mayordo / ROM 873021 ; b) “ Malaise trap w pans / 1° forest edge. 700m / 9° 17′N, 123° 15′E; c) “ Ochodaeus / sp. / det BD Gill 1994”; d) rectangular, red paper: “ TYPE ”; e) red paper: “ Ceratochodaeus / darlingi n. sp. / HOLOTYPE ♂ / J.-B. Huchet det. 2019”. Genitalia stored in a small glycerol vial, pinned under the specimen .

Allotype female ( ROM) labeled a–c as holotype; d) “ Ceratochodaeus / darlingi n. sp. / ALLOTYPE ♀ / J.-B. Huchet det. 2019”. ( Fig. 4–5 )

Diagnosis. This species has the body short, robust, strongly convex, and densely pubescent. It is predominantly dark reddish brown, but with orange-colored mandibles, clypeus, sides of the pronotum, anteromedian triangular patch on the pronotum, and two transverse elytral patches arranged in staggered rows. The underside and legs are orange-brown, and the antennae testaceous yellow. The stridulatory peg is present.

Description. Holotype male ( Fig. 1–3 , 6–9 ). Coleoptera : Scarabaeoidea: Ochodaeidae . Length: 10.6mm (from the apex of the mandibles to the apical part of the tergite VIII). Width: 5.9 mm. Head: Transverse, sub-hexagonal, dark reddish-brown, gradually narrowed behind the eyes. Surface shiny, long pubescent, the setae obliquely directed backwards; surface microreticulate with medium setiferous granules separated from each other by a distance substantially equal to their diameter. Labrum transverse, dorsally convex, hyaline, long pubescent, strongly emarginate in the middle front. Eyes large, globose, strongly produced laterad. Anterior clypeal membrane transverse, trapezoidal, in thin tegumentary plate overhanging the labrum. Frontoclypeus elevated, obliquely sloping forward, arched rearward, surmounted by a strong sub-pyramidal horn, abruptly truncated at apex. In upper view, the truncation delineates a transverse, concave, kidney-shape area ( Fig. 6 ). Mandibles subequal, falciform, slightly concave dorsally, the apex and outer edge distinctly darkened. Mentum oblong, subquadrangular, emarginate and weakly depressed in front, the surface finely microreticulate, pubescent along the lateral margins (see Fig. 7 ). Antenna 10-segmented, 3-antennomere club, testaceous, shiny, the outer club segment distinctly brightened and pubescent at the upper edge. Pronotum transverse, strongly convex, the lateral edges and base fringed with setae, the outline entirely margined, the marge distinctly widening in the middle of the base forming a transverse bulge in an portion extending on both sides up to the level of the humeral callus. Anterior margin deeply emarginate behind the head, with a thin hyaline membrane in front. Front angles obtuse, projecting forward, the posterior ones regularly rounded. A short median longitudinal furrow at base, not reaching the middle forward. Pronotal surface densely granulate; granules shiny, setose, the setae obliquely directed anteriorly; surface shiny, bicolored, dark reddish brown with two orange-colored lateral areas and a distinct darkened fovea in the middle of each side; a longitudinal orange-colored medio-discal macule not reaching the anterior edge in front. Elytra transverse, their color coarsely similar to that of the pronotum with two rows of orange transverse patches. The first row located at the ¼ front, the second one located behind the middle ( Fig. 1, 3 ). The anterior band extending from interstria II to VII, interrupted on interstria III. The second row, arranged in staggered orange spots, extending from interstria II to VII. Surface with well impressed striae, consisting of sunken medium points, separated by 1.5 to 2 x their diameter; elytral punctuation strong and tight consisting of small setose granules on a microreticulate background, the minute setae oriented backward. Humeral callus well developed; a second callus present in the apical declivity at the level of the 5th and 6th interstriae. Scutellum in elongated triangle, the lateral edges slightly convex, the surface with few scattered setose medium punctures. Abdomen strongly convex with six visible sternites (III–VIII). Surface smooth, with few scattered minute setose granules. The anterior margin of each sternite with a line of coarse granules bearing long setae, distant from each other by at least 1× their diameter. A median process originating on the sternite IV as a convex bulge, extending backwards, ending acutely at the level of the penultimate sternite (sternite VII) (this feature is absent in females). This process, asymmetrical, is located, in ventral view, on the left side, flanked on either side by a strong longitudinal depression, this depression clearly more marked on the right side. Tergite VIII (pygidium) pubescent, the punctuation consisting of small close granules embedded on a microreticulate background. Metasternal process subplanar with a thin median darkened groove in the anterior half; mesocoxae widely separated. Stridulatory apparatus (sternite VI) present. Legs: Protibia quadridentate externally, the median tooth barely visible, the basal tooth very reduced; internal side with a strong acute pollex obliquely directed forward, darkened apically. Femurs without accessory teeth, their surface with two parallel rows of setose punctures. Upper spur of metatibia of equal length to that of the first metatarsus. Genitalia: Aedeagus with elongated phallobase, curved dorsoventrally, acuminate apically; parameres short, symmetrical, distinctly divergent at apex. Endophallus well developed with two main sclerites ( Fig. 9 ) and two barely perceptible accessory sclerites.

Sexual dimorphism. As described for the genus, namely the presence, in males, of a strong frontoclypeal horn, truncated apically ( Fig. 1, 3 , 6 ) [the female with a single arched carina ( Fig. 4–5 )], the pronotum more convex dorsoventrally, and by the presence of a median abdominal apophysis acuminate posteriorly (absent in females).

Etymology. This taxon is dedicated to my colleague Christopher Darling, Royal Ontario Museum, Canada, who collected this new species on Negros Island.

Distribution. Philippines, Central Visayas, Negros Oriental ( Fig. 10 ).

Both specimens were obtained from Malaise trap at a forest edge, an ecotone on ridge between a pristine valley and disturbed habitat ( Fig. 11a, b ).

Remarks. This new species is morphologically close to Ceratochodaeus montgomeryi from Luzon. The species differ by the shape of the apical trunctature of the horn, kidney-shaped in C. darlingi new species, suboval with the outline distinctly sinuous in the middle of the front and basal margins in C. montgomeryi . Male protibiae slender in C. darlingi , distinctly broader and stout in C. montgomeryi . Finally, although both of very reduced size compared to other species of the genus ( C. eliotti and C. vulcanodon), the endophallic sclerites of C. darlingi and C. montgomeryi are morphologically distinct.

Ecology. Little is known about the natural history of Ochodaeidae . Most species are nocturnal and strongly attracted to light, but sometimes also collected in ground traps containing beer or vinegar. In recent years, the systematic use of Flight Interception Traps (FIT) and Malaise traps has provided many specimens of species previously considered very rare and only represented in collections by a small number of individuals, or even by the single holotype. From the discovery of basidiomycete spores within the intestinal content of Pseudochodaeus estriatus (Schaeffer) , Carlson and Ritcher (1974) suggested that these insects are mycophagous and feed upon hypogean fungi. The presence of numerous basidiomycete basidiospores within the intestinal contents of C. darlingi new species confirms herein the fungal habits of these insects.

Figures

Figure 10. Location map showing the type locality of Ceratochodaeus darlingi Huchet, new species, on Negros island.

Figure 11. Type locality of Ceratochodaeus darlingi Huchet, new species, on Negros island. a) Malaise trap used for collecting the specimens. b) Malaise trap in front view, a local collector nearby (photos courtesy: C. Darling, ROM).

Figures 1–3. Ceratochodaeus darlingi Huchet, new species, male holotype. 1) Habitus, dorsal view. 2) Labels. 3) Habitus, latero-dorsal view.

Figures 4–5. Ceratochodaeus darlingi Huchet, new species, female allotype. 4) Habitus, dorsal view. 5) Habitus, lateral-dorsal view.

Figures 6–7. Ceratochodaeus darlingi Huchet, new species, male holotype. 6) Head, dorsal view. 7) Head, ventral view.

Figures 8–9. Ceratochodaeus darlingi Huchet, new species, male holotype. 8) Abdomen in ventral view, the median acuminate process located on the ventrites indicated by an arrow, the median dotted line emphasizing the asymmetric location of the process. 9) Male genitalia. a) Aedeagus in lateral-dorsal view, the inner sac not everted (Scl: endophallic sclerite). b) Close-up view of the two main sclerites of the endophallus.