Oplognathus helmenreichi Ohaus, 1905

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 : 71-76

Oplognathus helmenreichi Ohaus, 1905

Figs 1c–e , 2b–d , 3c–d , 4i–m , 6 , 7e –h, 8c, f , 9

Hoplognathus helmenreichi Ohaus, 1905: 322 .

Hoplognathus helmenreichi – Ohaus 1914a: 301 (species description); 1918: 12 (catalogue). — Blackwelder 1944: 235 (catalogue).

Hoplognathus helmreicheni – Ohaus 1914a: 302 (species description); 1918: 12 (catalogue); 1934: 42 (catalogue). — Blackwelder 1944: 235 (catalogue).

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

Hoplognathus helmreicheni var. maculicollis – Ohaus 1914a: 302 (description, infrasubspecific name, unavailable).

Diagnosis

Elytra reddish brown to orange yellow; male with clypeus moderately trilobate, lobes distinctly rounded, sides parallel ( Figs 1c–e , 3c–d ); antennal club 1.8× longer than antennomeres 2–7 combined ( Fig. 3c– d ); females with club length 1.5× longer than antennomeres 2–7 combined; last maxillary palpomere cylindrical in both sexes ( Fig. 4l ); mentum longer than wide, anterior margin slightly sinuous, posterior angles rounded ( Fig. 4m ). Elytral striae distinctly marked; elytral epipleuron of female slightly dilated; mesoventral process long, apex rounded, never reaching anterior coxae ( Fig. 8c, f ); apex of the mesotibia with 7–13 spinules; apex of metatibia with 14–22 spinules in both sexes.

Material examined ( Figs 1c , 2b )

Holotype ARGENTINE • ♂, holotype of Oplognathus helmenreichi Ohaus, 1905 ; “ Buenos Aires ” [white typewritten label]; “ Pelidnota Helmenreichi Buenos Aires ” [white handwritten label]; “ Typus !” [red typewritten label]; “ Hoplognathus Helmenreichi Ohaus ” [red handwritten label]; ZMHB.

Syntypes COUNTRY UNKNOWN • ♂, syntype of Oplognathus helmenreichi var. maculicollis Ohaus, 1914 ( Figs 1d , 2c ) • “ Typus!” [red typewritten label]; “Helmr.” [white handwritten label]; “ H. Helmenreichi Ohs. v. maculicollis Ohs. ” [red handwritten label]; “SYNTYPE Hoplognathus helmenreicheni var. maculicollis Ohaus, 1914 labelled by MFNB 2017 ” [red typed label]; ZMHB • ♀, syntype of Oplognathus helmenreichi var. maculicollis Ohaus, 1914 ( Figs 1e , 2d ); “♀” [white typewritten label with black border]; “Cotype” [red typewritten label]; “Helmr.” [white handwritten label]; “SYNTYPE Hoplognathus helmenreicheni var. maculicollis Ohaus, 1914 labelled by MFNB 2017 ” [red typed label]; ZMHB.

Additional material (six specimens)

COUNTRY UNKNOWN • “Ohaus determin. 1913 Hopl. Helmenreichi v. maculicollis Ohs. Cotype ♀ ”; NHMW.

BRAZIL – Minas Gerais • 4 ♂♂; Leme do Prado, Estação Ecológica de Acauã ; 23 Dec. 2003; M.F. Vasconcelos leg.; UFMG-ICO . – Paraná • 1 ♂; Curitiba ; 3 Aug. 2010; Oliveira leg.; CERPE .

Redescription

Male holotype ( Figs 1c , 3c , 4i–m , 6a–c , 7e–f )

SIZE. Total length: 17.6 mm; width across prothorax: 9.1 mm.

COLOUR. General aspect metallic dark green and reddish brown; head, pronotum, legs and venter metallic green, elytra reddish brown.

HEAD. Clypeus with surface rugose, densely punctate, larges punctures, gradually coalescent from disc to margins; apex trilobate, lobes rounded, sides parallels with the slightly converging apex. Frontoclypeal suture obsolete, sinuous, forming an angle on disc. Clypeus and frons subequal in length. Frons subquadrangular, moderately punctate, more densely posteriorly, with medium to large punctures, coalescent in the margins ( Fig. 3c ). Maxillary palpi with last palpomere cylindrical, sensorial area oval, occupying two thirds of dorsal area ( Fig. 4l ). Mentum near 1.2× longer than wide, anterior margin weakly sinuous, almost straight, posterior angles rounded ( Fig. 4m ); surface sparsely punctate with scattered setae, punctures large. Antennal club 1.8× longer than antennomeres 2–7 combined.

THORAX. Pronotum with surface moderate to densely punctate, increasing density towards sides; anterior angles acute; sides slightly truncate ( Fig. 3c ). Propleuron slightly concave, surface rugose, and moderately setose. Scutellar plate moderately punctate, punctures bigger on disc. Elytral striae distinctly marked; first interstriae with puncture thin, dense. Epipleuron flattened, sparsely setose, minute setae. Mesoventral process long with rounded apex, never reaching procoxal base ( Fig. 8c, f ); surface punctate and densely setose. Metasternum densely punctate and densely setose. Procoxa densely punctate and sparsely setose. Profemur sparsely punctate and sparsely setose. Mesofemur moderately punctate and densely setose. Metafemur flattened, broad, sparsely punctate, and with sparse posterior setae. Protibia with surface densely punctate, bigger punctures, C-shaped punctures on disc; apex with 10 distinct setae. Mesotibia with two transverse carinae: proximal carina marked by four spinules, distal carina marked by five spinules, surface moderately punctate and sparsely setose, short setae; apex with 11 spinules. Metatibia similar to mesotibia, but more robust and with 19 apical spinules.

ABDOMEN. Pygidium subtrapezoidal, apex slightly rounded, surface rugose, minute setae sparsely disposed on margins. Ventrites with surface sparsely setose, fine and short setae. Parameres similar in length, irregularly V-shaped bifurcated, bifurcation base rounded; apical lobes well defined, left lobe smaller than right lobe; left lateral expanded in lateral view, parabolic expansion; right expansion obsolete ( Figs 6a–c ).

Male variation

Size: total length: 17.2–19.0 mm; width across prothorax: 7.5–9.1 mm. General aspect orange-brown; head, pronotum and scutellar plate may have yellowish maculae ( Fig. 1d–e ). Suture frontoclypeal vary in the degree of sinuosity. Pronotum can be more or less truncate at sides. Surface of mesofemur varies from moderately to densely punctate. Mesotibia with proximal and distal carina marked by 4–7 spinules; apex truncate with 7–13 spinules. Metatibia with 14–22 spinules in the apex, distal carina with 5–11 spinules, and proximal carina with 5–8. Parameres vary from parabolic curvature of the aedeagus to the truncate curvature, as well as, in the degree and shape of lateral expansion, it can be longer and more parabolic ( Figs 6d–f , 7e–h ).

Female ( Fig. 1e )

Similar to males in general aspects, differentiating in the following aspects: pronotal maculae more elongate; clypeus rounded; frontoclypeal suture distinct, with central curvature; antennal club 0.7× smaller than in males, 1.5× longer than antennomeres 2–7 combined. Pronotum with parallel sides and anterior angles more rounded. Elytral epipleuron slightly rounded, distinct depression above epipleuron. Protarsomere I as long as protarsomeres II–IV combined.

Type locality

Oplognathus helmenreichi was originally described from Buenos Aires ( Argentina) ( Ohaus 1905), and this locality was later contested by the author ( Ohaus 1914a) while describing the variety, O. helmenreichi var. macullicolis . This species can actually be found in the north and northeast of Minas Gerais state in the Jequitinhonha River Valley ( Ohaus 1914a). Accordingly, after the examination of three more males from the same region, we agree with Ohaus (1914a) and disregard the occurrence of O. helmenreichi in Argentina.

Remarks

We consider the type of Oplognathus helmenreichi a holotype since Ohaus (1905) mentions only a single specimen. For Oplognathus helmreicheni var. maculicollis Ohaus (1914a) had multiple specimens available. ICZN (1999, Article 45.6.1.) states that a name “is infrasubspecific if its author expressly gave it infrasubspecific rank, or if the content of the work unambiguously reveals that the name was proposed for an infrasubspecific entity”. Furthermore, the Article 45.6.4. (ICZN 1999) clarifies that a name “is subspecific if first published before 1961 and its author expressly used one of the terms “variety” or “form” (including use of the terms “var.”, “forma”, “v.” and “f.”), unless its author also expressly gave it infrasubspecific rank, or the content of the work unambiguously reveals that the name was proposed for an infrasubspecific entity, in which case it is infrasubspecific”. In the time Ohaus described Oplognathus helmenreichi var. maculicollis he already clearly separated between species, subspecies and varieties as an article from the same year (see Ohaus 1914b) shows where he described new taxa on the species, subspecies and infrasubspecific levels. Therefore, Oplognathus helmenreichi var. maculicollis is an unavailable name. Although the pair of syntypes of O. helmenreichi var. maculicollis examined have some distinct characteristics of the holotype – such as yellowish colour, smaller size, less dense punctures and the male genitalia almost parallel sided, the other specimens examined show many similarities both with the syntypes and with the holotype. The variation of these characteristics was also observed within the other species of the genus. Despite these variations, mouthpart characters (like mentum shape, maxillary palpus shape) and mesoventral process remained constant in the eight specimens examined. Thus, Oplognathus helmenreichi var. maculicollis does not present a unique combination of character states that justify validating it to species or subspecies status.

Distribution

Brazil: Minas Gerais: Grão Mogol, Leme do Prado. Paraná: Curitiba? (Fig. 9).

No other specimen of O. helmenreichi was subsequently collected in Buenos Aires, or anywhere else in Argentina ( Ohaus 1914a). One part of the material of O. helmenreichi var. maculicollis was labelled “Helm., Brasilia, XXII, 1853” and the other part “Serra do Grão Mogor, 1846” [Municipality of Grão Mogol, Minas Gerais]. Ohaus (1914a) then made it clear that the most probable locality of this species would be the north of Minas Gerais State (Grão Mogol) and not Buenos Aires, corresponding to the known distribution of the genus. Thus, we agree with Ohaus (1914a) and disregard Buenos Aires as a locality for this species, as well as for the genus Oplognathus . One male of the examined material is labelled as being from Curitiba, Paraná, South of Brazil, but the origin is doubtful, since this single specimen was found in a didactic collection of the Federal University of Paraná.

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. 6. Aedeagus in dorsal (a, e) and lateral view (b–c, d–f). a–c. Oplognathus helmenreichi Ohaus, 1905, holotype, ♂ (ZMHB). d–f. O. helmenreichi var. maculicollis Ohaus, 1914, 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.