Helictopleurus rudicollis ( Fairmaire, 1898 )

Rossini, Michele, Montanaro, Giulio, Montreuil, Olivier & Tarasov, Sergei, 2024, Towards computable taxonomic knowledge: Leveraging nanopublications for sharing new synonyms in the Madagascan genus Helictopleurus (Coleoptera, Scarabaeinae), Biodiversity Data Journal 12, pp. e 120304-e 120304 : e120304-

Helictopleurus rudicollis ( Fairmaire, 1898)

Oniticellus rudicollis Fairmaire 1898: 399

Liatongus rudicollis : Fairmaire 1901: 134 (new combination);

Helictopleurus rudicollis : d’Orbigny 1915: 418 (new combination); Gillet and Boucomont 1927: 111; Balthasar 1941: 89; Lebis 1960: 72; Paulian 1986: 106; Montreuil 2005 a: 133;

Helictopleurus hypocrita Balthasar 1941: 134 (syn. nov.) (Fig. 2 c ); Montreuil 2005 a: 133; Bezdĕk and Hájek 2012: 321;

Materials

Type status: Syntype. Occurrence: individualCount: 1; sex: male; lifeStage: adult; preparations: dry; disposition: in collection; occurrenceID: 48AD10D1-BDF2-5606-9926-550DC3BF2A4D; Taxon: scientificName: Oniticellus rudicollis Fairmaire, 1898 ; acceptedNameUsage: Helictopleurus rudicollis ; parentNameUsage: Scarabaeinae; namePublishedIn: Fairmaire L. (1898) Matériaux pour la faune coléoptérique de la région malgache (6 e note). Annales de la Société entomologique de Belgique, 42, 390–439; class: Insecta; order: Coleoptera ; family: Scarabaeidae ; genus: Helictopleurus ; specificEpithet: rudicollis ; taxonRank: species; scientificNameAuthorship: Fairmaire, 1898; nomenclaturalCode: ICZN; taxonomicStatus: accepted; Location: continent: Africa; country: Madagascar; locality: Antsianaka ; Identification: identifiedBy: L. Fairmaire; Event: eventDate: 1892-01 / 06; year: 1892; verbatimEventDate: 1 er Semestre 1892; Record Level: institutionCode: MNHN; basisOfRecord: PreservedSpecimen

Type status: Holotype. Occurrence: individualCount: 1; sex: male; lifeStage: adult; preparations: dry; disposition: in collection; occurrenceID: C866E3F5-DE1C-5A4A-8ACA-AF935D19F874; Taxon: scientificName: Helictopleurus hypocrita Balthasar, 1941 ; namePublishedIn: Balthasar V. 1941. Eine reihe von neuen coprophagen scarabaeiden (67. beitrag zur kenntnis der 235 scarabaeidae, col. Mitteilungen der Munchen Entomologische Gesellschaft 31 (1): 164-184.; class: Insecta; order: Coleoptera ; family: Scarabaeidae ; genus: Helictopleurus ; specificEpithet: hypocrita ; taxonRank: species; scientificNameAuthorship: Balthasar, 1941; nomenclaturalCode: ICZN; taxonomicStatus: subjective synonym; Location: continent: Africa; country: Madagascar; Identification: identifiedBy: V. Balthasar; Record Level: institutionCode: NMPC; basisOfRecord: PreservedSpecimen

Type status: Holotype. Occurrence: individualCount: 1; sex: male; lifeStage: adult; preparations: dry; disposition: in collection; otherCatalogNumbers: MALP 0550; occurrenceID: F8B71464-2E59-53F9-B084-F77380DA3C9B; Taxon: scientificName: Helictopleurus furcicornis Lebis, 1960 ; namePublishedIn: Lebis E. 1960. Insectes, coléoptères Scarabaeidae , Helictopleurina. Faune de Madagascar, 11, 25–130; class: Insecta; order: Coleoptera ; family: Scarabaeidae ; genus: Helictopleurus ; specificEpithet: furcicornis ; taxonRank: species; scientificNameAuthorship: Lebis, 1960; nomenclaturalCode: ICZN; taxonomicStatus: valid; Location: continent: Africa; country: Madagascar; Record Level: institutionCode: MNHN; basisOfRecord: PreservedSpecimen

Type status: Holotype. Occurrence: individualCount: 1; sex: male; lifeStage: adult; preparations: dry; disposition: in collection; otherCatalogNumbers: MALP 531; occurrenceID: C36B8CD0-9D24-50D5-9BF2-6CD92F1F601F; Taxon: scientificName: Helictopleurus splendidus d'Orbigny, 1915 ; namePublishedIn: d'Orbigny H. 1915. Synopsis d’un genre nouveau d’Oniticellides ( Scarabaeidae Coprini) spécial à Madagascar. Annales de la Société entomologique de France, 84, 402–434; class: Insecta; order: Coleoptera ; family: Scarabaeidae ; genus: Helictopleurus ; specificEpithet: splendidus ; taxonRank: species; scientificNameAuthorship: d'Orbigny, 1915; nomenclaturalCode: ICZN; taxonomicStatus: valid; Location: continent: Africa; country: Madagascar; verbatimLocality: Fianarantsoa; Record Level: institutionCode: MNHN; basisOfRecord: PreservedSpecimen

Type status: Paratype. Occurrence: individualCount: 1; sex: male; lifeStage: adult; preparations: dry; disposition: in collection; otherCatalogNumbers: MALP 532; occurrenceID: 13D0EB26-F1D1-5DCE-97EA-261312FC473C; Taxon: scientificName: Helictopleurus splendidus d'Orbigny, 1915 ; namePublishedIn: d'Orbigny H. 1915. Synopsis d’un genre nouveau d’Oniticellides ( Scarabaeidae Coprini) spécial à Madagascar. Annales de la Société entomologique de France, 84, 402–434; class: Insecta; order: Coleoptera ; family: Scarabaeidae ; genus: Helictopleurus ; specificEpithet: splendidus ; taxonRank: species; scientificNameAuthorship: d'Orbigny, 1915; nomenclaturalCode: ICZN; taxonomicStatus: valid; Location: continent: Africa; country: Madagascar; verbatimLocality: Bémarivo, Région Est; Record Level: institutionCode: MNHN; basisOfRecord: PreservedSpecimen

Diagnosis

Helictopleurus rudicollis belongs to the rudicollis group and can be readily distinguished from other members of the group, H. rubricollis and H. cribricollis , by the pronotum and elytra metallic-green and shiny and elytra with lighter spots (elytra dark, dull, not metallic and without spots in both H. rubricollis and H. cribricollis ). The separation of H. rudicollis from H. splendidus is still unclear, as the male of the latter was never described. Nonetheless, the following female characters could help in separating the two species: punctation of posterior third of pronotum evenly distributed in H. rudicollis (sparser in H. splendidus ); lateral pronotal angles more expanded laterally in H. splendidus ; median tubercle of frontal carina simple in H. rudicollis (bilobate in H. splendidus ).

Distribution

This species is widely distributed across eastern Madagascar, from the Sambava to Ifanadiana District (Fig. 3 a ).

Taxon discussion

Balthasar (1941) described H. hypocrita on a unique specimen, but no exact collecting locality was given. Without checking the holotype, Lebis (1960) assigned this species to the giganteus group, suggesting that the original description could refer either to H. undatus (Olivier, 1789) or H. rudicollis . Ever since, H. hypocrita appeared only in one checklist ( Montreuil 2005 a). In this study, we investigated and compared the external and genital morphology of the holotype of H. hypocrita with the type specimens of the members of the rudicollis group and we eventually concluded that H. hypocrita is a junior subjective synonym of H. rudicollis ( H. hypocrita syn. nov.).

The Helictopleurus rudicollis group includes four species ( Lebis 1960, Montreuil 2005 b): H. rudicollis , H. cribricollis Lebis, 1960 , H. rubricollis Lebis, 1960 and H. splendidus d’Orbigny, 1915 . However, after examination of the syntypes of H. furcicornis Lebis, 1960 , we deem that this species too could be considered an additional member of the same group. Helictopleurus furcicornis shares several characters with H. rudicollis : body metallic-green; elytra with a series of orange-brownish spots; long yellow setae along the lateral edges of the pronotum; tip of the parameres strongly curved downwards. However, the two species differ in the shape of the male frontal horn (conical in H. rudicollis ; wider, with parallel sides and distally emarginated in H. furcicornis ), pronotal punctuation (denser in H. rudicollis ) and lighter spots on elytra (single transversal row in H. rudicoliis ; elytral interval 4 with two additional spots, one in proximity of the base, one close to the apex).

Helictopleurus rudicollis was described from Tamatave and Antsianaka, which correspond to today’s Toamasina and Lac Alaotra, respectively, both located in central-eastern Madagascar ( Viette 1991). Instead, the type series of H. splendidus includes specimens from Bémarivo (probably referring to a locality along the Bemarivo River, north-eastern Madagascar), Fianarantsoa and Fort Dauphin (central-eastern and south-eastern Madagascar, respectively) ( d’Orbigny 1915) (Fig. 3 a ). Despite the multiple dung beetle surveys carried out over the last 20 years in the type and nearby localities, no additional specimens of H. splendidus have been captured or identified. On the other hand though, H. rudicollis is considered one of the most abundant species in these localities ( Rahagalala et al. 2009). Therefore, given that the two species are morphologically very similar, the above statements raise a series of questions that need further investigation: (i) Have all the " H. rudicollis " specimens collected so far been identified correctly? (ii) is H. splendidus a valid species? (iii) If so, maybe this latter species has become extinct?

During a recent collecting expedition in Madagascar (February 2022), we collected a series of conspecific specimens in Mandraka Park (- 18.914266, 47.92477098), Analamazoatra (- 18.939524, 48.418760) and Mantadia (- 18.84549399, 48.42834902) National Parks, including one male, that may belong to H. splendidus . However, a detailed comparison of the morphology of these specimens with the types of H. splendidus and H. rudicollis is needed to confirm this identification and the taxonomic status of H. splendidus .

Figures

Figure 2 c. Dorsal habitus and labels of the holotype of H. hypocrita;

Figure 3 a. H. rudicollis (blue circles; black arrows indicate the type locality) and H. splendidus (red circles; red arrows indicate the type localities);