A new species of Colacus Ohaus, 1910 (Coleoptera: Scarabaeidae: Dynastinae) from the Mata Seca biotope of Brazil, and notes on Colacus morio Ohaus, 1910 Author Sobral, Rafael Author De Morais, José W. Author Grossi, Paschoal C. text Zootaxa 2019 2019-11-07 4695 2 159 167 journal article 24943 10.11646/zootaxa.4695.2.5 7f34a626-f4fc-4484-83cf-ea8a2fdc963c 1175-5326 3531280 CC111070-3A28-4D52-A26F-B808CC200975 Colacus rubrofemoratus Sobral, Morais , & Grossi, new species ( Figs. 1–5 ) Diagnosis. Colacus rubrofemoratus is distinct from the other species of the genus as it has the cephalic tubercle transverse, emarginate on its apex ( Fig. 2 A–B), and red legs ( Fig. 1B ), visible even when specimens are walking ( Fig. 1C ); whereas the other species have a conical cephalic tubercle with a sharp apex ( Fig. 7D ), and black legs ( Fig. 6B ). The new species is slightly similar to Colacus morio , from which it can be distinguished by the mandibles convex, leaf like, almost semicircular ( Fig. 3E ), and by the rectangular ocular canthi ( Fig. 2C ); versus the mandibles slightly concave ( Fig. 7B ), and sinuous ocular canthi ( Fig. 7C ) in C. morio . FIGURE 1. Male of Colacus rubrofemoratus . A , Habitus in dorsal view, black arrow indicating the fourth protibial tooth; B , habitus in ventral view; C , living specimen on a log. Scale bars: 3 mm. FIGURE 2. Head and pronotum of Colacus rubrofemoratus . A , Head in frontal view, white arrow indicating the apex of cephalic tubercle; B , head and anterior portion of pronotum in dorsal view, white arrow indicating the pronotal fovea; C , canthus in dorsal view; D , head and pronotum in lateral view, black arrow indicating pronotal tubercles. Scale bars: A–C , 1 mm; D , 3 mm. Description. Holotype . Male. Color: Head, pronotum, and elytra black; ventral surface and appendages, mainly coxae, femora, trochanters, and tarsi dark red ( Fig. 1B ). Head: Frons and clypeus densely punctate; punctures coalescent. Punctures on vertex slightly sparser medially and grouped laterally, wider or with same width than punctures on clypeus. Cephalic tubercle transverse, base as wide as clypeal apex, apex of tubercle emarginate ( Fig. 2A ). Clypeus obtusely acuminate with sides distinctly angulate, apex round ( Fig. 2B ). Ocular canthi rectangular, canthi apex straight ( Fig. 2C ). Antennae with 10 antennomeres, lamellae short at 0.9 times the length of antennomeres II–VII. Mouthparts: Labrum arcuate, anterior edge medially protruded, posterior edge concave ( Fig. 3D ). Mandibles apically round, becoming narrower and straight basally; in dorsal view, mesal brush dense near molar plate, becoming sparser apically, not reaching apical third of mandibles ( Fig. 3A ). In ventral view, mandibles with punctures deep and wide medially; shallow punctures surrounding apical and outer edges ( Fig. 3B ). Maxillae, in ventral view, densely setose on galea, with sparser and longer bristles on outer side of stipes. Galea almost reniform; palpifer reaching maxillary palpomere II ( Fig. 3C ). Mentum subtriangular, basally and laterally round, apex slightly acuminate; punctures deep and dense ventrally ( Fig. 3E ). Thorax: Pronotum convex, round, 3.5 times wider than head. Anterior margin with 2 small, oblique knobs forming an inconspicuous, small fovea ( Fig. 2B ). Pronotal punctures deep, punctures on disc annular and sparse, becoming denser on sides. Pronotal fovea with punctures smaller than on disc, almost smooth. Metasternal plate almost glabrous, punctures coalescent basally and laterally, surface almost smooth medially and apically with a few small, shallow punctures. Scutellar plate subtriangular, laterally weakly angulate, apex round; basally with larger punctures than apically; apex almost smooth. Elytra: Shape rectangular, 1.6 times longer than wide. Surface rugopunctate with weakly defined, subparallel striae; striae deeply punctate, punctures ocellate on disc becoming smaller near elytral suture. Elytral disc transversally wrinkled, wrinkles never reaching punctures near elytral suture. Humeral umbone not crossing elytral sides in posterior view, apical umbone short, more conspicuous. Punctures small, sparse on humeral and apical umbones. Legs: Protibia with 4 external teeth increasing in size distally, basal tooth reduced ( Fig. 1A ). Metafemur thickened, surface smooth with 1 posterior furrow with scattered setae. Abdomen: Tergite VIII convex, glabrous, shape transverse, 2.4 times wider than long; disc sparsely punctate, margins densely punctate; punctures annular and small anteriorly, coalescent posteriorly, wrinkled on edges. Sternite V as long as sternites IV–III combined. Sternite VI smooth; punctures small, merged with wrinkles on sides, disc barely punctate; distally setose at middle; setae as long as sternite VI. Aedeagus: Parameres symmetric in caudal view with sides parallel, apex slightly dilated, wider than base; surface glabrous ( Fig. 4B ). In lateral view, parameres almost as long as phallobase, and with an oblique, ventrolateral carina ( Fig. 4A ). FIGURE 3. Mouthparts of Colacus rubrofemoratus . A , Left mandible in dorsal view; B , left mandible in ventral view, white arrows indicating shallow punctures on mandible; C , left maxilla in ventral view, black arrow indicating maxillary palpifer; D , labrum in dorsal view; E , head in ventral view, black arrow indicating outer edge of right mandible, white arrow indicating punctures on mentum. Scale bars: A–D , 1 mm; E , 2 mm. Measurements of holotype . Body length: 26.8 mm . Head width: 5.5 mm . Pronotal width: 12.3 mm . Elytral length: 16.8 mm . Elytral width: 10.1 mm . Protibial length: 6.4 mm . Female. Unknown. Paratype variation. Body length: 27.2–28.6 mm . Head width: 5.3–5.5 mm . Pronotal width: 12.1–12.4 mm . Elytral length: 16.8–17.6 mm . Elytral width: 9.6–10.1 mm . Protibial length: 6.4–6.5 mm . Paratypes are similar to the holotype but with pronotal punctures dense on disc and near posterior margin, frons with less coalescent punctures than holotype , and elytra with inconspicuous transverse wrinkles. Material examined. Holotype male (at CERPE ), labeled: a) “ BRASIL , MG, Berizal / 15.xii.2007 / Grossi , Rafael & Parizotto/ Coleta Manual ”; b) “ Colacus rubrofemoratus sp. nov. / HOLOTYPUS / Sobral , Morais & Grossi det. 2018” . Paratypes : Three males with same data as holotype at EPGC , one male at CERPE labeled: a) “ BRASIL , MG, Berizal / 18.xii.2012 / P.C. Grossi & G.A.R. Melo legs.”; b) Colacus rubrofemoratus sp. nov. / PARATYPE / Sobral , Morais & Grossi det. 2018”. FIGURE 4. Male genitalia of Colacus rubrofemoratus . A , Aedeagus in lateral view, white arrow indicating a ventral carina; B , parameres in dorsal view. Scale bars: 1 mm. Etymology. From the Greek, “ Rubro ” meaning “red”, “ femora ” for the segments of the legs and “ atus ” meaning “provided with”, in reference to the red color of the femora and trochanters ventrally. This name is an adjective in the nominative singular. Natural history. One specimen was found alive ( Fig. 1C ) walking diurnally on the ground and it was collected manually, at 1400 m . The other specimens were found dead at the same elevation. FIGURE 5. A , Known distribution map of Colacus species; B , Mata Seca biotope. Distribution. Colacus rubrofemoratus was found in northern Minas Gerais ( Fig. 5A ), in a transitional area known as Mata Seca between the Brazilian Caatinga, Atlantic Forest, and Cerrado biomes ( Fig. 5B ). The Mata Seca is one of the biotopes of the Cerrado characterized by vegetation adapted to low annual precipitation and with leaf deciduousness resulting from drought. This environment shares some floral similarities with Caatinga, Atlantic Forest, and Cerrado, being a mosaic with typical vegetation such as some species of Malvaceae , Fabaceae , Cactaceae , and Araceae ( Ribeiro & Walter 1998 ) . Unfortunately, the Mata Seca is in continuous deforestation and in the process of severe biodiversity loss. In spite of Colacus rubrofemoratus has been found so distant from the Argentinian species (approximately 2700 km ), they share the similarity of occurring in open dry areas with xeric vegetation. Possibly, the variations in the range of the South American dry biomes throughout the Pleistocene, such as the Puna, High Monte, and Cerrado, have allowed the dispersal of Colacus species and subsequent isolation of populations within the Cerrado during the contraction of these dry biomes.