Contribution to the knowledge of Podischnus Burmeister, 1847 (Coleoptera: Melolonthidae: Dynastinae) with the description of two new species from Brazilian Amazon Forest

Two new Podischnus Burmeister, 1847 species are described here: Podischnus limeirai sp. nov. from Gurupi region, Maranhão state, Brazil, the easternmost distribution of the genus; and Podischnus cleidecostae sp. nov. from the Acre state, Western of Brazilian Amazon Forest. New diagnostic characters are illustrated and discussed for the genus. An illustrated identification key for all Podischnus species, and an up-to-date distribution map for the Brazilian species of Podischnus are provided. Moreover, we propose the inclusion of P. limeirai sp. nov. in the Red List of Threatened Species (IUCN) due to the fast loss of the Oriental Amazon Forest remnant fragment in that region. Key-Words. Deforestation; New taxa; South America; Oryctini; Threatened species.

Most of Podischnus species has its natural history unclear and there is only one study about the biological aspects of P. agenor performed by Eberhard (1979). Also, Neita-Moreno & Orozco (2009) described the larva and pupa of this species with a brief note about its natural history.
As a part of our studies on Neotropical phytophagous scarab beetles, we describe here two new unusual Podischnus species from Brazilian Amazon: one from Maranhão state, Gurupi region, eastern Amazon, located within Belém endemism area, and other from Acre state, Madeira province, west Amazon (Morrone, 2006). A known distribution map for these new species along with the other two Brazilian ones is provided, as well as an illustrated identification key for all Podischnus species. Furthermore, due to the fast deforestation of the remaining medium-sized fragment of the Amazon forest at Maranhão state, is proposed the inclusion of the new species described for the Gurupi region in the Red list of Threatened Species (IUCN).   (Olivier). (B) P. sexdentatus (Taschenberg). (C) P. oberthuri Sternberg. (D) P. limeirai sp. nov. (E) P. cleidecostae sp. nov. Scale bars: 2 mm. Duarte, P.R.M. & Grossi, P.C.: Two new species of Brazilian Podischnus Burmeister Pap. Avulsos Zool., 2020;v.60.special-issue: e202060(s.i.).22 4/15 Head: Clypeus bidentate; teeth separated in dorsal view by a broad, emarginated apex (Fig. 3B); horn at the subapical area long, curved backwards, acuminated apically; horn laterally covered by setigerous, basal punctures. Frons smooth at middle, only with few small punctures confined to the sides; interocular width 1.2× the transverse diameter of the eye. Eye canthus subtriangular, excavated, glabrous. Antennae with 10 antenomeres; club subequal in length to antennomeres 2-7; 1-4 cylindrical, 5-7 subquadrate. Mandibles bidentate; external margin exposed laterally to clypeus in dorsal view; outer tooth stronger than inner tooth. Mentum convex, base with sides rounded, narrowed towards apex, apex widened; surface moderately punctate, punctures setose.
Pronotum: Pronotal horn bent backwards in lateral view (Fig. 2D); horn base abruptly narrowed in posterior view; apex very broad, about four times wider than the basal width; in dorsal view slightly emarginate anteriorly (Fig. 1D), with anterior corners rounded; posteriorly with two rounded areas separated by a deep longitudinal sulcus in posterior view; dorsal surface of pronotal horn finely punctate, ventral surface densely covered by short, yellowish setae. Pronotal border complete, anteriorly broader at the midline; surface of lateral margin medially with groups of coalescent, C-shaped punctures; anterior surface unequally declivous, declivity near 45°, slightly concave, with a medial groove extended posteriorly to horn base; posterior area with a weak lateral concavity on each side near horn base.
Scutellum: Subtriangular in shape, surface with a V-shaped-grouped, coalescent punctures, and C-shaped punctures among them.
Elytra: Surface completely chagrined, with roughness only observed under high magnifications; sutural striae well visible, remaining discal striae barely impressed; disc finely, irregularly punctate; area above humerus smooth; lateral area bellow humerus with three incomplete rows of large, ocellate punctures; punctures decreasing in size posteriorly.
Legs: Protibiae quadridentate; mesotibiae with one proximal, three medial, and two distal teeth on external surface; metafemora with a row of seven setigerous punctures near to anterior ventral margin (Fig. 3D); metatibiae with one proximal, two medial and two distal teeth on external surface.
Venter: Surface nearly completely setose. Prosternal process triangular, flat in lateral view, prolonged between anterior coxae, with setae confined to the base and apex. Abdomen: Ventrite II with a complete row of setae; ventrites III-V with incomplete row of setae; ventrite VI completely bordered by setae at posterior margin; surface of ventrites II-V strongly rugose near to anterior margins, roughness confined to sides, disc nearly smooth, only with few, fine, scattered punctures; ventrite VI rugose at the sides, disc smooth, apex widely emarginate. Tergite VII with arched stridulatory apparatus (Fig. 5D); stridu-latory apparatus formed by two bands of innumerous small tubercles; tubercles transverse, well-marked near the base, scattered about one tubercle of distance, becoming less scattered and finely marked toward apex. Tergite VIII strongly convex in lateral view; surface with rugopunctures on lateral and basal areas, disc finely punctate, glabrous; area near apical margin with a slight concavity on each side; posterior border glabrous.

Paratypes, male variation
Differing from the holotype in the following aspects: Body length ranging from 44.0-45.0 mm and body width from 20.5-21.0.
Head: Cephalic horn with lateral setae almost reaching its midline.
Legs: Metafemora ventrally with a row of 5-10 setigerous punctures near the anterior margin.
Abdomen: Basal area of tergite VIII with two transverse bands of setae on each side; posterior border with setae confined to apex.
Aedeagus: Parameres symmetric, laterally narrowed at the outer margins in dorsal view, outer margins rounded posteriorly on apical half, inner margins setose (Fig. 6D); in lateral view with a strong, longitudinal excavation; outer margins visible in ventral view, ventral plate slightly truncated apically (Fig. 7D).

Female (Fig. 8D)
Very distinct from male holotype in the following characteristics.
Etymology: The specific epithet "limeirai" is a patronym honoring to Dr. Francisco Limeira de Oliveira, curator of the Coleção Zoológica do Maranhão and the responsible of the current knowledge of the entomological fauna from "Meio Norte" region comprising the states of Maranhão and Piauí, respectively. Diagnosis: Podischnus cleidecostae sp. nov. is distinguished from other Podischnus species by the following combination of characters: cephalic horn in major males with broad, compressed apex, or with a small subapical tooth in lateral view (Fig. 2E); prosternal process short, confined below the anterior coxae (Fig. 4D); stridulatory apparatus separated by a medial row of setose punctures confined to the base of tergite VIII (Fig. 5E); parameres laterally convergent on basal half (Fig. 6E).
Color: Surface dark reddish brown.
Pronotum: Anterior angles strongly acute (Fig. 4B); medial portion of discal area obtusely declivous in lateral view, with a weakly marked ridge extended to horn base in dorsal view; posterior area with a horn, projected backwards in lateral view, apically broad; horn apex finely punctate, strongly emarginated anteriorly, densely setose ventrally, at middle with a pit, extending posteriorly in a medial sulcus (Fig. 1E). Lateral surface strongly rugopunctate at the midline. Scutellum: Moderately punctate; punctures C-shaped, irregularly scattered.
Elytra: Surface almost completely covered by fine punctures; area above humerus with a row of six large, C-shaped punctures; lateral area bellow humerus with three incomplete rows of punctures; first and second rows extending until posterior area, punctures decreasing in size towards posterior area; third row with large punctures only.
Legs: Protibiae quadridentate. Mesotibiae with three medial and two distal teeth on external surface. Metatibia with four medial and three distal teeth on external surface.

Abdomen:
Ventrite II with a complete medial row of transverse, setose punctures; ventrites III-V with rows confined to sides; ventrite VI covered by setae on posterior margin. Ventrites II-V rugose on sides, smooth on disc; ventrite VI rugose near anterior margin. Tergite VII with stridulatory apparatus formed by two parallel carinate bands; carinae well-marked and tubercle-like in shape near the base, gradually becoming finely marked and more transverse towards apex; basal area between carinae with a medial row of setose punctures, becoming irregularly scattered towards apex (Fig. 5E). Tergite VIII strongly rugose on sides near apical margin; discal area weakly punctate; transversal area near basal margin moderately rugopunctate.

Paratypes, male variation
Differing from holotype in the following characteristics. Head: Minor male with clypeal apex deeply emarginated; cephalic horn short, with no modifications; frons strongly punctate on sides. Cephalic horn in major males lacking apical expansion in lateral view, only with a small subapical tooth, or only with enlarged apex, with no subapical tooth.
Pronotum: Minor male with horn not as broad as in major males, tubercle-like shaped; dorsal horn surface with pit sometimes absent.

Female: Unknown.
Etymology: The specific epithet is a patronym honoring to Prof. Dr. Cleide Costa for her 80 th anniversary, as well as for her tremendous contribution to the systematics of Neotropical Coleoptera.

DISCUSSION
Podischnus limeirai sp. nov. and P. cleidecostae sp. nov. are unusual species because the pronotal horn is bent backwards, and this feature is unique among the other species of the genus. Besides, among the material studied we noticed new features to identify P. agenor and P. sexdentatus, two species so far distinguished only by the basal punctures on the sides of the pronotal horn (absent in P. agenor, present in P. sexdentatus) (Endrödi, 1985;Gasca-Álvarez et al., 2008;Sanabria-García et al., 2012). The stridulatory apparatus and the ventral plate of the parameres (see the identification key above) are consistent features to differentiate both species. The stridulatory apparatus is an important new character for the identification of Podischnus species.
Podischnus limeirai sp. nov. deserves special attention because so far the known distribution is restricted to the easternmost limit of the Amazonian biome. This means not only a new state record of the genus (Maranhão) but also an expansion of its distribution to the east. Moreover, Podischnus limeirai sp. nov. is the unique species of the genus restricted to an endemism area within the Amazonian biome, and does not occur in sympatry with any other Podischnus species.
The Belém endemism area where P. limeirai sp. nov. occurs is localized at the Pará biogeographic province sensu Morrone (2006). It is distributed from eastern Pará state to western Maranhão state, bounded to the west by the Tocantins river (Pará state) and to the east by the Pindaré river (Maranhão state) (Almeida & Vieira, 2010). According to da Silva et al. (2005), the Amazon is a biogeographical heterogeneous area constituted by a set of eight endemism centers delimited by major rivers, each of them with its particular evolutionary history. Studies based on distribution of different taxa of lizards (Ávila-Pires, 1995), primates (Silva & Oren, 1996), amphibian (Ron, 2000), birds (Silva et al., 2002) and also riodinid butterflies (Hall & Harvey, 2002) support this delimitation of Amazonian endemism areas. Gasca-Alvarez et al. (2008) showed that P. sexdentatus occurs in the states of Acre and Amazonas. Podischnus agenor has a more eastern distribution within the Amazon, but extending up to the west of Tocantins river, not reaching the Belém endemism area. Ratcliffe (1976) inferred that the complex networks of the Amazonian rivers, which raised on intergla-cial periods, are the responsible for the subspeciation of Strategus surinamensis Burmeister, 1847 in S. surinamensis surinamensis Burmeister, 1847 (distributed north of the Amazon River), and S. s. hirtus Sternberg, 1910 (distributed south of the Amazon River). This climatic event can be associated with the allopatric speciation and distribution of P. limeirai sp. nov. The Belém endemism area is the most deforested among the Amazon endemism areas, with loss of 124,801 km², over 62.2% of area, occasioned mainly by agricultural expansion, being classified as critically endangered (Braz et al., 2016).
The type locality of P. limeirai sp. nov. is situated within the "Reserva Biológica do Gurupi" (Rebio) and "Terra Indígena Awá/Guajá", Gurupi region, Maranhão state (see above). This region hosts endangered and endemic mammalian and birds (Oren & Roma, 2011;Oliveira et al., 2011). The Rebio Gurupi and adjacent indigenous lands are the last continuous Amazon forests remnants of Maranhão state, being considered one of the most endangered areas of Brazilian Amazon Forest in 2011 (Oliveira, 2011). The conservation of Gurupi region is determinative for maintenance of a variety of unique, endemic or threatened species (Oliveira, 2011). Therefore, we propose to include P. limeirai sp. nov. in the Red List of Threatened Species (IUCN), according to its endemic distribution mentioned above, in Near Threatened (NT) category according the (IUCN, 2012) Red List criteria.