Dichotomius (Luederwaldtinia) malyi

Dataset
Taxonomic revision of the Dichotomius speciosus (Waterhouse, 1891) species group (Coleoptera: Scarabaeidae: Scarabaeinae): Rank
SPECIES: Published in
Maldaner, Maria E., Nunes, Rafael V., Vaz-De-Mello, Fernando Z. (2015): Taxonomic revision of the Dichotomius speciosus (Waterhouse, 1891) species group (Coleoptera: Scarabaeidae: Scarabaeinae). Zootaxa 3986 (5): 549-560, DOI: 10.11646/zootaxa.3986.5.2

Classification

kingdom
Animalia: phylum
Arthropoda: class
Insecta: order
Coleoptera: family
Scarabaeidae: genus
Dichotomius: species
Dichotomius malyi

description

Variation. Female: Very similar to male. As in other species of the group, females of D. malyi bear a plain straight fore calcar and their 6 th abdominal ventrite has the same medial width as the others.

diagnosis

Diagnosis. Within the group, D. malyi is the only species that bears a single cephalic tubercle in both sexes, lacking carinae, horns, depressions, projections or other ornaments both on head and pronotum (Fig. 5 A, B). It is also the only species within the group bearing ocellate punctures on the pronotal disc, in a manner similar to that of the species assigned to the batesi species group (Nunes & Vaz-de-Mello 2013). To avoid misidentifications, one should consider the males fore calcar (Figs. 1 B, 1 C), which is falciform (simple in batesi) and its Atlantic Forest distribution (batesi species group are all Amazonic).

discussion

Remarks. According to the key by Nunes & Vaz-de-Mello (2013), this species could be diagnosed as belonging to the Dichotomius batesi species group, because it bears a knob / tubercle on the head and its pronotal disc bears ocellate setose punctures. However, unlike the species in the batesi group, males of D. malyi bear an apically curved and falciform fore calcar, setae restricted to the sides of the abdominal ventrites and are blue on the ventral surface (some species in the D. batesi complex do have bluish reflections, but in that case, the integument is dark grey or black).

distribution

Distribution and conservation. Species of the Dichotomius speciosus group (locality data unknown for D. malyi) are restricted to the highlands (above 1000 m) of the Brazilian Atlantic Forest domain. The group’s geographical distribution comprises three mountain ranges: Serra da Bocaina in São Paulo state (Dichotomius alvarengai); Serra da Mantiqueira on the limits of Rio de Janeiro, Minas Gerais, and São Paulo states (Dichotomius speciosus); and Serra Geral including parts of Rio Grande do Sul, Santa Catarina, and Paraná states (Dichotomius opalescens) (Fig. 7). Species with known localities are all allopatric, and their occurrence is limited by lower areas. Other Atlantic forest mountain ranges that reach similar altitudes are: the Caparaó range, on the border between Minas Gerais and Espírito Santo states; and the Serra dos Órgãos range, in Rio de Janeiro state. Both ranges (mainly Serra dos Órgãos) have been collected extensively and no specimens of the speciosus group have been found in either one so far. For Dichotomius malyi, São Paulo is given as the type locality, which may refer to the state or not, unfortunately no more information is available; and no localities named São Paulo are known in the other two mountain ranges cited for the group. The southeastern and southern regions of Brazil have the best known dung beetle faunas in Brazil because the earliest entomological collections were done in Rio de Janeiro and São Paulo states (Vaz-de-Mello 2000) and those areas thus have a long and extensive collection history. Therefore, we have long term records available for some species of the speciosus group, which allows us to draw some conclusions on their conservation. The conclusions are based mainly on distributional records, because natural history data are almost nonexistent. We base our conservation status assessments on the extent of occurrence (B 1 criteria), which is predicted by drawing a polygon using the points where the species were recorded (IUCN 2015). D. malyi n. sp. is promptly discarded from this analysis due to the lack of distributional information, thus we considered this species as Data Deficient (DD).

distribution

Distribution. Unknown, probably São Paulo state, Brazil.

etymology

Etymology. Named after Vladislav Malý, Czech scarabaeoidologist, in whose collection the only known specimens have been found, and who has been so kind to donate the only known male to CEMT to be designated as the holotype.

materials_examined

Holotype. Male: Length: 12 mm. Width (pronotum): 6 mm. Dorsal and ventral surface barely shinny, dark blue. Head: Clypeal surface almost entirely smooth, bearing punctures only on gena and near eyes. Cephalic process almost absent, consisting of single tubercle. Clypeo-genal junction rounded. Pronotum: Simply convex, lacking knobs, anterior declivity or excavations. Pronotal disc with ocellate punctures evenly spaced, mainly concentrated at the center of it, anterior angles and along posterior pronotal border. Anterior angles rounded. Hypomeron: With dense lateral setae, similar to that found on metasternum and femora. Mesosternum: Smooth, shinny, lacking setae or punctures, expanded medially. Metasternum: Bearing dense setae at sides and near borders of the anterior lobe. Setae similar to those on hypomeron, femora and mesepisternum. Elytra: Striae deeply impressed with conspicuous points. Punctures separated by their diameter. Interstriae smooth and lacking strong reflections, with very fine punctures (30 x). Legs: Ventral surface of anterior femur with strong ocellate punctures all over its extension. Middle and hind femora with few setigerous points. Anterior and posterior borders of all femora bearing dense setae, as those on the hypomeron, metasternum and mesepisternum. Middle tibiae with green sheen. Abdomen: setae restricted to the sides of the abdominal ventrites, these with ocellate punctures following the anterior margin. Pygidium: As long as wide and lacking punctures or reflections. Paramera: dorsal view: with a rounded and divergent apexes. one lateral view, gradually tapering to apex, having an acute angle (Fig 5 C, D).

Name

Synonyms: Dichotomius alvarengai; Dichotomius speciosus
Homonyms: Dichotomius (Luederwaldtinia) malyi