Oplognathus bahianus Ohaus, 1912

Carvalho, Tamara G., Seidel, Matthias & Grossi, Paschoal C., 2021, Taxonomic revision of the genus Oplognathus MacLeay, 1819 (Coleoptera: Scarabaeidae: Rutelinae: Rutelini), European Journal of Taxonomy 764 (1), pp. 62-84 : 76-81

Oplognathus bahianus Ohaus, 1912

Figs 1f–g , 2a , 3b , 4e–h , 5d–f , 7i–m , 8b, e , 9

Hoplognathus bahianus Ohaus, 1912: 650 .

Hoplognathus bahianus – Ohaus 1918: 12 (catalogue); 1934: 42 (catalogue). — Blackwelder 1944: 235 (catalogue).

Oplognathus bahianus – Machatschke 1972: 5 (catalogue). — Krajcik 2007: 90 (catalogue).

Diagnosis

Male with truncate, strongly, trilobate clypeus, rounded in females; clypeus with divergent sides ( Fig. 3b ). Antennal club of the males 1.5× longer than antennomeres 2–7 combined. Male with last maxillary palpomere fusiform ( Fig. 4g ), cylindrical in females. Mentum broad, as long as wide, anterior margin notched, posterior angles rounded ( Fig. 4h ). Elytral striae distinctly marked. Mesoventral process short and slightly flat, with apex slightly rounded ( Fig. 8b, e ). Apex of the mesotibia with 9–12 spinules and apex of the metatibia with 18–20 spinules, females with 24–27 spinules at the apex of the metatibia.

Material examined

Syntype BRAZIL • ♂, syntype of Oplognathus bahianus Ohaus, 1912 ( Figs 1f , 2a ); “ Typus!” [red typewritten label]; “ C. Bts. Obrth. ” [white handwritten label]; “SAntonio da Barra Prov. de Bahia Ch. Pujol 1890” [white typewritten label]; “ Hoplognathus bahianus Ohs. ” [red handwritten label]; ZMHB .

Additional material (six specimens)

BRAZIL – Minas Gerais • 1 ♂; Berizal; 15 Dec. 2007; Grossi, Rafael & Parizotto leg.; CERPE • 1 ♂; Berizal ; Dec. 2001; P. Grossi leg.; CERPE • 3 ♂♂, 1 ♀; Águas Vermelhas ; Nov. 1991; E. Grossi leg.; EPGC .

Redescription

Syntype male ( Figs 1f , 3b , 4e–f , 5d–f , 8b, e )

SIZE. Total length: 20.8 mm; width across prothorax: 10.5 mm.

COLOUR. General aspect with dorsal surface yellow gold and ventral surface metallic green; head, legs, and pygidium from cooper to reddish brown with metallic green reflections.

HEAD ( Fig. 3b ). Clypeus subquadrangular, surface rugose, sparsely setose; apex strongly trilobate, truncate, margins bowed inward, sides clearly divergent; ventral surface moderately punctate and moderately setose. Frontoclypeal suture straight. Clypeus 1.3× longer than frons. Frons densely punctate, punctures coalescent laterally. Last maxillary palpomere fusiform, distinctly flattened ( Fig. 4g ); sensorial area oval, occupying two thirds of dorsal surface. Mentum 1.05× wider than long, subequal, anterior margin notched, posterior angles rounded ( Fig. 4h ); surface densely punctate, large punctures; surface sparsely setose, setae as long as the length of the labial palpus. Antennal club 1.5× longer than the antennomeres 2–7 combined.

THORAX. Pronotum with surface moderately and uniformly punctate, thin punctures; surface glabrous; anterior angles rounded; maculae obsolete: two anterolateral maculae as cooper slight spots, and two lateral maculae heterogeneous ( Fig. 3b ). Propleuron concave, moderately setose and moderately punctate. Scutellar plate sparsely punctate. Elytra with 10 deeply marked striae, interstriae practically obsolete in general, first interstriae with dense puncture; epipleuron flattened, glabrous. Mesoventral process short with rounded apex, never reaching the apex of the mesocoxa, surface sparsely setose and densely punctate ( Fig. 8b, e ). Metasternum densely punctate, and densely setose. Procoxa rugose, surface sparsely setose. Profemur moderately setose. Mesofemur flattened, surface densely, and uniformly punctate; moderately setose. Metafemur flattened, broader, surface moderately, and uniformly punctate; moderately setose. Protibia moderately setose in the medial-inner portion, external portion sparsely setose; surface densely punctate, not uniform, big punctures, coalescent on the lateral portion; apex with a group of 11 setae. Mesotibia with surface sparsely setose dorsally, setae longer than wide mesotibia; surface densely setose ventrally; densely punctate, punctures big and small, not uniformly scattered; external surface with two carinae, proximal one short, marked by 3 spinules, and a distal complete, and oblique carina with 8 spinules; apex truncate with 13 spinules. Metatibia similar to mesotibia, but with 19 spinules on the apex.

ABDOMEN. Pygidium subtrapezoidal, sparse setae disposed in the margins, disc glabrous. Ventrites with surface sparsely setose posteriorly in the ventrites II–IV, and restricted to the lateral of ventrite VI, moderate punctuation. Parameres transverse, apex emarginated like V-shaped, with the left side distinctly shorter and broader, the right side slightly sinuous, base notched, concave; right lateral paramere divergent, straight, toward the apex with a concavity; apex with an only oblique lobe, transverse and anterior face straight; left lateral paramere broadly rounded and expanded ventrally, long expansion, apically of two lobes, external lobe projecting outwardly; base of parameres sinuous with median recess in V-shape ( Fig. 5d–f ).

Male variation

Size: total length: 20.0– 20.8 mm; width across prothorax: 10.0– 10.5 mm. Frontoclypeal suture can be slightly sinuous. Mentum can have the anterior margin more or less curved, but all specimens show the notched type; mentum vary from 1.3–1.8× longer than frons. Pronotal and elytral punctation are distinctly marked, but one specimen has them very smooth. Surface on the scutellar plate varies from sparsely to moderately punctate. Mesoventral process is predominantly short with a rounded apex, one specimen has it more acute. Apex of protibia vary from 9–12 setae. Proximal carina of mesotibia varies by 2–3 spinules, and the distal carina varies by 5–9 spinules; apex truncate with 9–13 spinules. Metatibia with 18–20 spinules in the apex, distal carina with 7–11 spinules, and proximal carina with 3–5 spinules. Parameres vary in the degree of lateral inclination, lobes of parameres may be more or less pronounced, the lateral projections vary in length ( Fig. 7i–m ).

Female ( Fig. 1g )

Similar to the male, differing from it in the following aspects: body usually more truncate, globose, distinctly convex. Total length: 22.1 mm, width across prothorax: 11.1 mm. Head with rounded clypeus, convergent sides; antennal club 0.7× shorter than in male. Last maxillary palpomere cylindrical, sensorial area straighter. Pronotal maculae obsolete; elytral epipleuron broader; protibial spur distinctly thinner; tarsal claws similar, without differentiation, anterior tarsus shorter; apex of metatibia with 24–27 apical spinules. Sixth sternite subtriangular, and more densely punctate almost rugose.

Type locality

Brazil. Bahia: [Santo Antônio da Barra], currently the municipality of Condeúba (Fig. 9).

Remarks

Ohaus (1912) did not state the number of specimens and therefore, we consider the single type specimen as a syntype. Oplognathus bahianus is the most distinctive species of the genus, with the males presenting a strongly trilobed clypeus. However, this character does not fit the original diagnosis of the genus (based on the type species O. kirbii ), where the clypeus was described with this character being less evident. Although being a secondary sexual character, the clypeus has been used as the main diagnostic character of the genus. After this study, despite concerning only one sex, the trilobed cypleus is the best character to distinguish O. bahianus . Another relevant character to distinguish this species is the mesoventral process, which is not salient and simply rounded, vs acute and salient in the two other species.

Distribution

Brazil. Bahia: Condeúba; Minas Gerais: Águas Vermelhas, Berizal (Fig. 9).

Oplognathus bahianus was described by Ohaus (1912) from Santo Antônio da Barra in Bahia. This locality received the denomination of Condeúba in 1889, and is located in the south-central region of the state in the Bahia Semiarid Region, near the north of Jequitinhonha Valley. This species has the northernmost distribution in Brazil, being also found in the north of Minas Gerais in the Jequitinhonha

Fig. 9. Geographic distribution of Oplognathus MacLeay, 1819 . River Valley Region, an ecotone characterized by transition from the Atlantic Forest, Cerrado and Caatinga, with a high degree of endemism.

Figures

Fig. 1. a–b. Oplognathus kirbii MacLeay, 1819. a. Neotype, ♂ (NHMUK). b. Female specimen (MZUSP). c. O. helmenreichi Ohaus, 1905, holotype, ♂ (ZMHB). d–e. O. helmenreichi var.maculicollis Ohaus, 1914. d. Syntype, ♂ (ZMHB). e. Syntype, ♀ (ZMHB). f–g. O. bahianus Ohaus, 1912. f. Syntype, ♂ (ZMHB). g. Female specimen (EPGC). Scale bar = 5 mm.

Fig. 2. Labels. a. Oplognathus bahianus Ohaus, 1912, syntype, ♂. b. O. helmenreichi Ohaus, 1905, holotype, ♂. c–d. O. helmenreichi var. maculicollis Ohaus, 1914.c. Syntype ♂. d. Syntype ♀. e. O. kirbii MacLeay, 1819, neotype, ♂.

Fig. 3. Head and pronotum details. a. Oplognathus kirbii MacLeay, 1819, male specimen (ZMHB). b. O. bahianus Ohaus, 1912, syntype, ♂ (ZMHB). c. O. helmenreichiOhaus, 1905, holotype, ♂ (ZMHB). d. O. helmenreichi var. maculicollis Ohaus, 1914, syntype, ♂ (ZMHB). Scale bar = 1 mm.

Fig. 4. Mouthparts. a–d. Oplognathus kirbii MacLeay, 1819 (ZMHB). e–h. O. bahianus Ohaus, 1912 (ZMHB). i–m. O. helmenreichi Ohaus, 1905 (ZMHB). a, e, i. Right mandible. b, f, j. Right maxilla. c, g, l. Detail of the last maxillary palpomere. d, h, m. Mentum. Scale bar = 1 mm.

Fig. 5. Aedeagus in dorsal (a, e) y lateral view (b–c, d, f). a–c. Oplognathus kirbii MacLeay, 1819 (ZMHB). d–f. Oplognathus bahianus Ohaus, 1912, syntype, ♂ (ZMHB). Scale bar = 1 mm.

Fig. 7. Variation in male genitalia. a–d. Oplognathus kirbii MacLeay, 1819 (a-b: CEMT; c-d: ZMHB). e–h. O. helmenreichi Ohaus, 1905 (ZMHB). i–m. O. bahianus Ohaus, 1912 (CERPE). Scale bar = 1 mm.

Fig. 8. Patterns of mesoventral process. a, d. Oplognathus kirbii MacLeay, 1819 (MZUSP). b, e. O. bahianus Ohaus, 1912 (ZMHB). c, f. O. helmenreichi Ohaus, 1905 (CERPE). Scale bar = 1 mm.