Revision of the Megasoma (Megasoma) gyas (Jablonsky in Herbst, 1785) species group (Coleoptera, Scarabaeidae, Dynastinae)

Abstract The taxa of the genus Megasoma Kirby, 1825 (Coleoptera, Scarabaeidae, Dynastinae) related to M. gyas (Jablonsky in Herbst, 1785) are revised. Megasoma (M.) gyas is recognized as a monotypic species restricted to the Caatinga biome of northeastern Brazil. Megasoma gyas rumbucheri Fischer, 1968, is considered as a new synonym of M. gyas. The “long-horned M. gyas” is recognized as a separate polytypic species M. (M.) typhon (Olivier, 1789) with the nominative subspecies occurring through the Mata Atlântica biome of Brazil, from Bahia to São Paulo states and M. (M.) typhon prandii Milani, 2008 restricted to a small area in the state of Santa Catarina, South Brazil. Megasoma gyas porioni Nagai is considered as a new synonym of M. typhon typhon. The “short-horned M. gyas” occurring in Minas Gerais, São Paulo, and southwestern Bahia, is recognized as a separate new species and described as M. (M.) hyperionsp. nov. The paper includes an historical research and the redescriptions of the other nominal species of the genus. Distribution maps and a key to species in the M. (M.) gyas species group (males and females) are also provided.


Introduction
Megasoma (Megasoma) gyas (Coleoptera, Scarabaeidae, Dynastinae), locally known as "besouro de chifre" or "besouro com chifre" or "grande besouro", is perhaps the most interesting species among all the large sized South American Megasoma. Unlike its "naked" related species, i.e. the species of the Megasoma actaeon (Linnaeus, 1758) group, it displays a thick cover of short shiny setae on the whole dorsum, a feature shared with M. anubis (Chevrolat in Guérin, 1836) and M. joergenseni Bruch, 1910. Through the examination of type material as well as of large series of specimens from several localities, it was possible to re-define the species and to isolate three taxa which deserve a separate species or subspecies status. In this paper we describe a new species distributed in open Cerrado areas, as well as in some transitional areas of Cerrado and Caatinga, ranging from São Paulo to Bahia states. Additionally, we propose the use of the name Megasoma (Megasoma) gyas over Megasoma rumbucheri, considered here a new junior synonym of the former, and the name Megasoma (Megasoma) typhon (Olivier, 1789) over M. gyas for the current "long-horned gyas".

Material and Methods
A total of 328 specimens were studied (all wild collected), deposited in following collections: BMNH: The Natural History Museum, London, UK (Maxwell Barclay) EPGC: Everardo and Paschoal C. Grossi Collection, Nova Friburgo, Rio de Janeiro, Brazil Marcgraf himself. A big part of those plates were rejoined into the Libri picturati now housed in Krakow, Poland. Among the subjects of the "Handbook" (Libri principis) of Libri picturati made by Marcgraf there is a beautiful plate showing a Megasoma gyas (Fig. 1). It was the first time that this species was brought to the attention of the Western world. Subsequently, another illustration, a poorly executed drawing of the same beetle, was provided in the work Historia Naturalis Brasiliae of 1648 by Piso and Marcgraf (Fig. 2). This plate was the one seen by Linnaeus (1758) and listed by him among the references he provided while describing Scarabaeus actaeon (Prandi 2018). Despite the poor quality of the drawing there is little doubt that it represents a Megasoma gyas, an interpretation supported by the accompanying text: "the body is covered by yellowish pilosity…the first section of the body is three-horned…". The chapter of the book dealing with Megasoma gyas is entitled "Enema rare conformationis" and the Megasoma beetle is there called "Taurus volans" (flying bull) together with other three beetles. Marcgraf's first xylography at page 246 (Fig. 2), and the related guache color image in Libri picturati ( Fig. 1) show clearly a short-horned Megasoma: this is the most relevant character pointing towards Megasoma gyas s.str.. George Marcgraf (1610-1644) was a German scientist, who, at the beginning of the Dutch expedition had a role of simple attendant of the famous physician Wilhem Piso, but day after day thanks to his enthusiastic work gained the favor of the Dutch Governor. Four were the books on the traditional Brazilian medicine written by Piso, eight the books on the complex of natural sciences written by Marcgraf, Historiae naturalium Brasiliae, decoded by Johannes de Laet (1593-1649), one of the directors of the Dutch west india Company, all those reunited by J. Maurits van Nassau in the main opera Historia Naturalis Brasiliae (1648), financed by van Nassau himself, after his return to Holland and four years after Marcgraf's death. The work Historia Naturalis Brasiliae, until the beginning of XIX century, represented a source of important information on Brazilian natural history for European scientists, including Linnaeus, who referred to it in his Systema Naturae, often using Marcgraf's (or Piso's) descriptions as the only basis for establishing his species names. Marcgraf's drawings and descriptions of course referred to the places that Marcgraf himself had visited, i.e. the old Dutch "Captaincy" of Northeast, which includes the current States of Paraíba, Pernambuco, Alagoas, Ceará, Piauí and Rio Grande do Norte. Marcgraf visited certainly also the north of State of Bahia, having landed in Salvador (now its capital city). Hence it is very likely that the information given by Marcgraf on Megasoma gyas refers to specimens observed or collected in those regions and then given to the Count J. Maurits. Post-Linnean scientific reports In 1785 Jablonsky described Scarabaeus gyas following the Linnean method: "...in the lower part of the head there is a horn, considerably wide but hidden, in the shape of a shovel, which the more it lengthens and the more it becomes wider, towards the end it ends in two long teeth…the armor is completely covered by yellow hair…in addition to this sickle-shaped horn the armor stretches downwards and both sides form a point…so it can also be called tricorn thorax…the elytra are thick and covered with yellow hair, which give to the insect an unusual sumptuous appearance…". The description is enriched by a precious color plate by Jablonsky himself. Carl Gustav Jablonsky (1756-1787) was a German scientist and illustrator, private secretary of the Queen of Prussia. Jablonsky's plates are worldwide recognized among the most beautiful plates produced in the age of enlightenment. Although "Natursystem alles bekannt...." is attributed to J. F. W. Herbst (1743-1807), it must be stressed that Jablonsky was the author of the first volumes of that work (Bousquet 2016), i.e. the first volume on butterflies and the first volume on beetles. Herbst took over the job after the untimely death of Jablonsky in 1787, at the age of 31. The ten volumes on beetles edited by Herbst and Jablonsky from 1785 to 1806 were probably the most important coleopterological work of the time. It is important to notice that also in the plate by Jablonsky the specimen of Megasoma gyas displays a short and wide cephalic horn. This particular shape of cephalic horn matches exactly with both the xylography and the painted picture in Marcgraf's publications. This is a key point because in 1789 the French scientist Guillaume Antoine Olivier (1756Olivier ( -1814 described Scarabaeus typhon and Scarabaeus laniger. The specimens of Olivier show two different features of the cephalic horn: long, thick, with a bifurcated apex the former, as shown in plate XVI at n. 252 (Fig. 5) and shorter, flatter and wider, with a very-well bifurcated apex the latter, as shown in plate XXVIII at n. 247 (Fig. 6). Olivier named his first specimen Scarabaeus typhon. Olivier's Scarabaeus typhon actually represents the species that up to now has been indicated as Megasoma gyas s.l. by the majority of authors. Burmeister (1847) established the synonymy between Megalosoma (a junior synonym of Megasoma Kirby) Typhon Olivier and Scarabaeus Gygas Jablonsky, giving priority to typhon. Later, in his Catalogus Coleopterorum of 1868, Harold mantained the synonymy of Burmeister, but in his addendum of 1871 changed his mind and established the priority of the name gyas over typhon saying (pag. 121-122): "...Der Jablonsky'sche Name gyas von 1785 hat die Prioritat; warum ihn Burmeister, der irrthumlich Gygas schreibt, zuruckgesetzt hat, ist ganz unerklarlich...". Also Scarabaeus laniger was incorrectly synonymized with M. typhon, always by Burmeister in 1847, considered as a "variation B" of the former, variation with a short horn (Cornu capitis brevius, in apice late furcatum, in ipsa basi tuberculatum). Before him, Kirby and Spence (1826) still had cited Typhon and lanigerum as separate species. But taking into account Harold's subsequent actions, the final result is that now laniger is correctly synonymyzed with the true Megasoma gyas, with which it shares the same specific characters. As regards the types of S. typhon and S. laniger , they are the specimens illustrated in the above mentioned plates of Olivier's Entomologie ou histoire naturelle des insectes (1789). For preparing his book Olivier travelled through England and Holland, with the goal to visit the private cabinets of collectors and to draw the species which were not available in Paris. It is likely that the specimens of S. typhon and S. laniger illustrated by Olivier were kept in collections he visited during the aforementioned trips. Olivier's reference under the description of Scarabaeus laniger "du cabinet de Mr. Juliaans" (from the collection of Mr. Juliaans) clearly indicates a Dutch family name. As for Scarabaeus typhon, the description of Olivier reported no localities, apart from the indication "du Musée Britannique" (from the British Museum). A recent search by Kazuho Kobayashi at the Natural History Museum in London revealed the presence of old specimens (ex Fry collection, dated around 1900) of classical "long-horned gyas" coming from Rio de Janeiro and Bahia. In his description Jablonsky listed three references. The first reference is "Fuessly Mag. I. p.37": in his work of 1778, Johan Caspar Fuesly reported a description of Voets' "Kaferwerk", Scarabaeus Goliath. The Latin description is the same reported by Jablonsky; there is also a numeric reference, Tab. XVII fig. 114. The third reference is "Goeze Ent, Beytr. I. p.56. n.11.": In his work of 1777 Johan August Ephraim Goeze also referred to "Voet. Scar. Terric. p. 27. No.114. t.17. f.114, giving a short latin description and the title "Goliath, der americaniche gelbe Bar". It is clearly the same insect of Fuesly. The second reference given by Jablonsky it is directly to "Scarabaeus Goliath. Voet. Scar, tab. 17. fig. 114". Johann Euseb Voets (1706-1778) was a Dutch physician, poet and entomologist. Voets died before the publication of Jablonsky, hence it is obvious that his description of Scarabaeus Goliath must be precedent, also because Fuesly in 1778 and Goeze in 1777 referred to him. His oldest work Catalogue raisonné ou systématique du genre des insectes, qu'on appelle Coleoptrées, was apparently published in livraisons starting in 1766. The first part was noticed, without further qualification, in April 1767 by the Gazette littéraire de l'Europe. Other parts were issued in 1776 and 1781. Finally, the work was completed and published by Bakhuysen in 1806, under the name Catalogus systematicus Coleopterorum. (Bousquet 2016). In the work of 1785, published after his death, "Beschreibungen and Abbildungen…" magistrally illustrated by G.W.F. Panzer, the already cited fig. 114 in plate XVII (our Fig. 3) shows perfect coincidence with Jablonsky's image. In fact Jablonsky wrote:…I tried to find a previous right description, but without result. Only Voet could see the insect in the collection of dr. Luchmann, and from there he represented it….For that Jablonsky used the image of Voet but …giving a more appropriate description, because I trust more on Voets' images than in his descriptions…and because Voets used a name "Goliath" which was already used by Linnaeus for another beetle without horn, I decided to use a name of a Titan, Gyas…   fig. 4. Scarabaeus gyas. In this plate the insect curiously appeared with the name of Scarabaeus esau. For this reason esau is considered as synonymous of gyas. Some plates appeared with the name of gyas, some other appeared with the name of esau. But no description of esau was provided. Therefore Voets' name Scarabaeus Goliath should have priority over gyas, however, Voets' Catalogus Systematicus Coleopterorum, fails to fulfill the requirements in the ICZN (Article 11.4) that for scientific names to be available, the entirety of the work in which they appear must be consistently binomial. Voets' names varied from 2 to 5 names in series, thus violating this rule, so none of Voets' names, even those which happened to be binomial, are available for use in modern scientific literature (see Alonso-Zarazaga andLyal (1999:8), following Sherborn (1902:liv), both citations in Bousquet 2016; see also interpretation of Krell (2012) on nomenclature and synonymy of Trichius). The original Luchmann's specimen is apparently lost. The iconography by Marcgraf and Voets/Jablonsky allows us to state that the first "gyas" described with the Linnaean scientific method had a short, flat and wide cephalic horn (Figs 3-4). Moreover, these evidences match the ancient description of Marcgraf, but we were then in the pre-Linnaean age, so the name was only a generic "Taurus volans". In this case, since Jablonsky's type doesn't match with Olivier's typhon, necessary changes in taxonomy need to be made. As for the type locality, then the travels to the "West Indies" meant also the coast near the Antilles, e.g. the Guyanas, Venezuela, and obviously, as we saw before, the Northern Coast of Brazil. In 1968 H. Fischer described M. rumbucheri (afterwards considered a subspecies of M. gyas: see Endrodi 1971) from Rio Pajeú, Planalto da Borborema, Pernambuco, Brazil. But this taxon actually displays the same characters of Marcgraf and Voets/Jablonsky original descriptions and is therefore a junior synonym of M. gyas (Fig. 8). Curiously in 1991 Kurt Rumbucher, to whom the Fischer's subspecies had been dedicated, while reviewing the variability of M. gyas challenged Fischer's claims, suggesting that the taxon rumbucheri fell within the variability of M. gyas s.l.. This opinion was supported by photos of M. gyas s.l. specimens in different sizes and tables with measurements. He did not examine the aedeagus and did not assess the geographical variability of the specimens he had examined. In 2003 S. Nagai described M. gyas porioni from Jaguaquara, Bahia state, Brazil, dedicated to the French entomologist Thierry Porion. The main character currently in use in order to distinguishing this subspecies is a long, normally straight, cephalic horn (despite the fact that in the original description is indicated as short and thicker in middle area), showing in the majority of cases a medium depressed zone, with a normally bifurcate apex (Fig. 15). This is a character we find in the typus of S. typhon Olivier. To conclude: no great external differences between the "long-horned gyas", M. gyas porioni and Olivier's S. typhon are found (Figs 5-7). The synonymy between M. gyas porioni and the "long-horned" gyas was also suggested by Grossi et al. (2008). Grossi, Vaz-de-Mello and Coelho Grossi (2008) hypothesized the presence of M. gyas in the state of Santa Catarina and the same year Leonello Milani described M. gyas prandii, from Santa Catarina State. This is the southernmost distributional record for M. gyas. Unlike the aforementioned subspecies, in this case both the geographical isolation and the peculiar morphology of the taxon leave little doubt about its validity as a subspecies, although, due to the present new arrangement, it must be considered as a subspecies of Megasoma typhon. None of the specimens of M. typhon prandii we have examined thus far displays a depressed area in the middle of the cephalic horn. All examined specimens show a thick long horn, often curved backwards, without any flattened area, and they have a distinctly bifurcate apex bent upwards. Besides the type locality, it was recently possible to find (author's unpublished data) other specimens of M. typhon prandii in old collections, from even more southern localities, labelled "Porto Alegre" (Rio Grande do Sul state in Brazil) or "surroundings of Porto Alegre" (around 1930, collection Ugo Bosia, Asti, Italy). Interestingly all those old specimens have an old label "M. typhon".

Revision of the species of Megasoma (Megasoma) gyas species-group
The Megasoma gyas species group, based on the present revision, consists of three species, one of them polytypic, with an overall distribution occupying most of Eastern Brazil, extending northwards up to Ceará (estimated latitude 3°42'02"N) and southwards to Rio Grande Do Sul (estimated latitude 30°00'44"S) states.
Megasoma ( (Fig. 9). The distribution range of this species overlaps a portion of the "subregioes nordestinas" of "Meionorte" and "Sertao" regions. (Fig. 10). The Caatinga biome (xeric shrubland and thorn forest) occupies an area of 497 thousands sq. miles, i.e. 10% of Brazilian territory. It's a recent biome located on an ancient seabed. This biome experiences long periods of drought, which can last up to 8 months. It is mainly composed by dry-Savannah (Brasilia's Botanical Garden; Coutinho 2016  Color. Uniformly dark ebony brown covered by a yellowish short, fine, thick pubescence; head, including horn, consistently black with the basal part near pronotum with yellowish sparse bristles. Head. Cephalic horn: short, projecting forwards and curved upwards. In lateral view flat, distally bent upwards. In dorsal view, narrower at the base, gradually broadened towards the distinctly forked apex. Apex U-shaped, with slightly divergent, long, tips (Fig. 8). Distance between tips 11.5 mm. Sides bordered with a weak rim hardly detectable, from base to mid-length. Dorsal side at the base with the relief of an almost imperceptible tooth, in this that is a major male; tooth totally absent in medium and minor males. Clypeus. Anterior edge concave, lateral angles with a small tooth, projecting forward, surface punctate. Mandibles. Each one with two small lateral teeth. Pronotum. The whole surface covered by a fine, dense, plentiful yellowish pubescence. Anterior angles projecting as small but elongate, sharp, parallel horns, slightly bent outwards; width at base 4.5 mm; length from base 8.5 mm; distance between apices of anterior horns 23 mm. Medial thoracic horn longer then laterals, length 15 mm., with a characteristic sickle-shaped form, dorsal side with a glossy black line, ventral side of medial horn with recumbent fine pubescence. PL/TH ratio 2.470. L/PL ratio 3.666, showing a fairly elongated feature of the body. Scutellum. Form triangular, each side with 8.1 mm, surface glabrous, finely punctate, apex smooth. Elytra. Surface covered by fine, dense, recumbent yellowish pubescence apart elytral suture and epipleure glabrous; EL/EW ratio 1.166. Elytral surface covered by variable number (two or three on each elytron) visible longitudinal ridges: sutural edge black, glabrous, punctate; the others pubescent ridges spaced out. Elytra in lateral view more convex proximally and then gradually flattened towards apex. L/EL ratio 1.571, elongate.  Pygidium. Strongly convex, with very fine, dense punctuation, hidden by thin, short, greyishbrown pubescence. Abdomen. Sides covered with short, very fine, yellowish-brown pubescence, medially almost glabrous. Legs. Fore tibia almost straight, inner apical edge strongly dilated inwards, 23 mm. in length. Anterior edge of protibia V-shaped. Lateral edge with three strong teeth, decreasing in size proximally, from the basal to the apical; basal tooth more distant from subapical tooth than the latter from apical tooth. Basal and subapical teeth large, triangular, thick, sharp, pointing rearwards; apical tooth short, pointing forwards. Inner apical spur strongly downcurved, as long as apical tooth. Fore tarsi length 25 mm. Aedeagus.
Parameres elongate and narrow, as in Tab. 2A-B. Variation, males. Major and medium males always with the apex of cephalic horn U-shaped, with long tips. (Fig. 8)  Female description. (Fig. 13). Dimensions. L: mm.54; PL: mm.16; PW: mm.23; EL: mm.34; EW: mm.30. Color. Uniformly black; elytra with 6/7 of its surface covered by grey-brownish dense pilosity. Head. Fronto-clypeal suture with a double conical tubercle. Clypeus. Surface finely punctate; lateral angles teeth like directed forwards and upwards; distance between apex mm.2; apical edge between angles concave. Pronotum. Surface dull, coarsely punctate-rugose, strongly convex; posterior medial carina mm. 8 long, ½ of total PL. Anterior angles obtusely projecting, yet with sharp tips. Lateral edges with presence of sparse bristles. Scutellum. Triangular, smooth, shiny, impunctate. Elytra. Surface rugo punctate at anterior region, glossy black; punctate black surface extending for 8 mm. in length, almost 1/7 of L. Elytral pubescence thick, uniform, with clearly visible longitudinal ridges, three or more for each elytron, almost equidistant. Dorsal longitudinal and lateral borders glossy black, with very fine punctuation. Pygidium. In lateral view, concave, with very fine punctuation. Surface in basal half covered with short, fine, reduced greyish pubescence; in apical half with scattered, erected brown-reddish setae. Abdomen. Sternites finely punctate, covered by short, yellowish-brown pilosity, except for a small central portion in the middle of sternites III-IV-V. Legs. Fore tibiae shorter than in males, TL mm.15, and shorter than tarsi, TF mm.17; external sides with three strong teeth almost equal in length, with the subapical tooth a little longer. Lateral teeth and inner apical spur smaller than in males. Measurements of females.   Megasoma (Megasoma) typhon ssp. typhon (Olivier, 1789) stat. nov. syn.: Megasoma gyas ssp. porioni, Nagai 2003. New synonymy Type material: the Holotype, i.e. the specimen illustrated by Olivier (Fig. 5) is probably lost (Kobayashi, after research at BMNH, personal communication, 2019). The designation of a neotype does not seem necessary since the species is well characterized and a search for the type in historical collections is still ongoing. The examined material, all kept in Universities and private collections, comes from several localities in Bahia, Minas Gerais, Rio de Janeiro and São Paulo states. Distribution. As explaned above, the classical "long-horned" beetle up to now called M. gyas gyas, is actually a distinct species which needs to be named M. typhon (Olivier, 1789). It occurs through the Mata Atlantica biome along the coastal areas of the Brazialian states of Bahia, Espirito Santo, Rio de Janeiro, São Paulo and Minas Gerais. The biome Mata Atlântica (Atlantic Rain Forest) occupies an area equivalent to 622.000 sq. miles, i.e. 13% of Brazilian territory and consists mainly of forests that run along the coastline from the State of Rio Grande do Norte to the State of Rio Grande do Sul. Due to its high human population density it is one of the most deforested areas of Brazil. Only 7% of its original vegetation remains, scattered over hundreds of mostly small fragments. The Mata Atlântica presents a diversified group of forest ecosystems and a variety of floristic structures connected to specific different climatic conditions, all them enjoying the humid winds that blow from the ocean (Brasilia's Bothanical Garden; Coutinho 2016). We have no records of M. typhon from Paraná state, being São Paulo state the southernmost record. This species shows an interesting variability in the shape of cephalic and thoracic horns, mainly in the flat or thin section of the former and in the tips of the latter. This variability however is found all over the distribution range of the species and therefore is an individual variability without a geographical meaning. Based on this new interpretation, M. gyas porioni Nagai is a synonym of M. typhon typhon. Material examined. The studied material is housed at CEMT, BMNH, INPA, MSNM, EUMJ, in EPCG and MPC collections and in many other private collections. The description below is based on a specimen from Bahia state, Jaguaquara locality, which closely resembles the specimen illustrated by Olivier. Other specimens from different localities are shown in order to illustrate the morphological variability uniformly found all over the distributional range of the species. The list of examined material enumerates more than 100 specimens (major ♂ 80%, minor ♂ 10%, ♀ 10%) coming from the following Brazilian localities: Jaguaquara, Amargosa, Salobrinho, Arataca, Ilhéus, Porto Seguro, Olivença, Una, Itamajú, Itabuna, Jequié (Bahia state); Ubatuba and some specimens labeled "province" of SP (São Paulo state); Teresópolis, Rio das Ostras, Guapimirim, Xerém, Nova Iguaçu (Rio de Janeiro state); Linhares (Espirito Santo state); Ipatinga, Vale do Rio Doce, Cataguases (Minas Gerais state).
Male redescription. (Fig. 15) Dimensions. L: mm. 79; TL: mm. 108; PL: mm. 23, PW: mm. 37; EL: mm. 54, EW: mm. 49; CL: mm. 38; PH: mm. 10.5. Color. Uniformly dark ebony brown covered by a yellowish short, fine, regular, pilosity; head, including horn, consistently black except for the basal part near pronotum with sparse bristles. Tips of thoracic horns glossy black. Head. Cephalic horn: long, projecting forwards and slightly curved upwards. In dorsal view, wider at the base, declining for a length of 6 mm. and then gradually broadened to a medial flattener zone with a maximal width of 5.5 mm., then declining again for a length of 13 mm., and finally gradually broadened towards the forked apex. Apex always V-shaped, with divergent tips (Fig. 15). This feature occours always in minor, medium and major males, with medial or longer horns. Sometimes the apex's tips of cephalic horn, in dorsal view, are slightly bent backwards, mostly in medium or small specimens. Distance between tips 8.5 mm.. Sides bordered with a weak rim easily detectable, from base to mid-length. Dorsal side at the base with the relief of a distinct tooth, with a max height of 3.5 mm. Clypeus. Anterior edge slightly concave, narrower than thickness of cephalic horn at the base, lateral angles with pointed tooth, projecting forward, surface punctate with presence of sparse bristles. Mandibles. Each one with two small lateral teeth. Pronotum. The whole surface covered by a regular, fine, dense, yellowish pubescence. Anterior angles projecting as elongate, sharp, divergent horns, distinctly bent outwards, width at base about 9.5 mm., length from base 10.5 mm., distance between apices of anterior horns 37 mm. Medial thoracic horn longer then laterals, length 17 mm., straight, dorsal side with a glossy black line, ventral side of medial horn with plentiful fine pubescence. PL/TH ratio 2.190. Scutellum. Big, triangular, 8 mm. long, 9 mm. wide, impunctate, glossy, with lateral bristles. Elytra. Covered by a very fine, dense, regular yellowish pubescence except along sutural edge and lateral borders; EL/EW ratio 1.102. Sutural glossy stripe black, limited by some visible ridges; three ridges, or more, almost equally spaced, on each elytron visible under pubescence. Elytra in lateral view bulging, but gradually flattened towards apex. L/EL ratio 1.462, showing an elongate feature of the body. Pygidium. Strongly convex, with very fine, yellowish pubescence. Abdomen. Laterally covered with very fine, short, reddish-brown pilosity, medially glabrous only for a little area of sternites. Legs. Fore tibia slightly rounded inwards, the inner edge strongly dilated at apex, FL, 26 mm.. The anterior edge of protibia V-shaped. Lateral edge with three strong teeth, decreasing in length from the basal to the apical tooth, but with the basal longer than the subapical; the basal tooth more distant from the subapical tooth than the latter from apical. Basal and subapical teeth large, thick, sharp, triangular, pointing rearwards; apical tooth very reduced, pointing forwards. Inner apical spur strongly curved ventrally, distinctly longer than the apical tooth. TF, 29 mm. Aedeagus. Overall appearence of the parameres more massive than in M. gyas, subrectangular, not narrow, as showed in Tab. 2C-D. Variation, males. As usual, development of cephalic and thoracic horns is allometric, but in medium and small specimens of M. typhon typhon with shorter cephalic horn, thoracic horns remain well developed. The tooth on dorsal side of cephalic horn is always present, in major, medium and small specimens.  Female description. (Fig. 17) Dimensions. L: 73 mm.; PL: 20 mm., PW: 32 mm.; EL: 49 mm.; EW: 41 mm. Color. Uniformly black; elytra covered for the 4/5 of the total surface by a yellow-brownish dense pilosity. Head. The middle of fronto-clypeal suture with a single tubercle. Clypeus. Finely punctate; anterior lateral angles projecting into a very small tooth directed forwards and a little upwards; distance between apices 3 mm.; apical edge between the angles concave. Pronotum. Dull, coarsely punctate-rugose, strongly convex; posterior medial carina 12 mm. long, more than ½ of total length. Anterior angles projecting, obtuse, with a blunt tip. Scutellum. Triangular, smooth, shiny, impunctate except for the lower apex. Elytra. Punctate-rugose glossy black on a dorsal, longitudinal area, at base extending for 10 mm., almost 1/5 of the EL; the sculpture is steadily fine towards the pubescent surface. The pubescent surface uniformly covered, with clearly visible longitudinal ridges, three or more ridges for each elytron, not equally spaced. Dorsal longitudinal edge of elytron and epipleure glabrous, glossy black, with very fine punctuation. Pygidium. In lateral view, profile concave, with very fine punctuation. Surface in basal almost smooth, with reduced greyish pubescence; in apical half with scattered, erected brown-reddish setae. Abdomen. Finely punctate, covered by short, brown-yellowish pilosity except for the medial central portion on sternites III-IV-V. Legs. Fore tibiae shorter than in the males, shorter than tarsi, 17 mm. long, fairly arcuate, with three lateral strong teeth. The basal and the subapical teeth equal in length; the apical tooth smaller. Inner side with a sligth dilatation at apex. Inner spur curved ventrally almost equal in length as apical tooth. Lateral and inner apical teeth smaller than in the males. TF length mm. 22. Measurements of females. The examined material riability ranges in mm. as follows. L: PW;[20][21][22][23][24][25][26][27][28][29][30][31][32][33][34]EL;; TF: 16-24; HL: 5-11.  (Fig. 20).
Distribution. This is the southernmost subspecies, nowadays restricted to the Serra do Mar region in the northern part of the Santa Catarina state. It displays a constant distinct morphology with respect to M. typhon typhon, which in addition to its geographic isolation, allows us to consider this population as a distinct subspecies. Material examined. The typical series in MPC collection, the paratype deposited in MSNM, other specimens in private Collections and an interesting old series (dated around 1930) in the Ugo Bosia Collection, Asti, Italy. The following redescription is based on a specimen from Serra do Mar, near Rio dos Cedros, above 180mt asl caught in 2010. After this date very few specimens have been found, suggesting that the subspecies could be threatened by the reduction of its habitat.
Male diagnosis (Fig. 20). A large Megasoma (size: L: 53-78, TL: 62-102; PL: 15-23; PW: 26-36; EL: 33-53; EW: [35][36][37][38][39][40][41][42][43][44][45][46], uniformly dark brown covered by a yellowish short, fine, regular, pubescence; head, including horn, consistently black. Head. Cephalic horn: long, projecting forwards and noticeably curved upwards. In dorsal view, slightly wider at the base and at the apex, but remaining almost subrectangular laterally, without a medial flattener zone. Apex always V-shaped, with divergent tips (Fig. 20). Pronotum: the whole surface covered by a regular, fine, dense, yellowish pubescence. Anterior angles projecting as elongate, sharp, weakely divergent horns. Medial thoracic horn longer then laterals, straight, dorsal side with a glossy black line. Elytra covered by a very fine, dense, regular yellowish pubescence except along sutural edge and epipleure. Elytra in lateral view not bulging, regularly flattened towards apex. Feature of the body elongate. Legs: Fore tibia slightly rounded inwards, the inner edge strongly dilated at apex. The anterior hedge of protibia Vshaped. Aedeagus as in Fig. 20c. Variation, males: the feature of the apex of cephalic horn is always V-shaped. The presence of a distinct tooth on the dorsal side of cephalic horn is always visible, also in medium and minor ♂. The feature of the body, in lateral view, in medium specimens remains almost flat, only very small specimens show sometimes a rounder body. Female diagnosis (Fig. 21).
Dimensions. L, in Allotype: mm. 64; PL: mm. 18; PW: mm. 27; EL: mm. 42; EW: mm. 38; HL: mm. 8. Color. Uniformly black; elytra with 3/4 of its surface covered by yellowishbrown dense recumbent pilosity. Head. The middle of fronto-clypeal suture with a single tubercle. In ventral view, inter-ocular distance length 3.4 mm.; transverse eye diameter width 3.5 mm. Clypeus. Finely punctate; anterior lateral angles projecting into a tooth directed forwards and upwards; distance between tips 2.5 mm.; apical edge between the angles concave. Pronotum. Dull, coarsely punctate-rugose, strongly convex; posterior medial carina 11 mm. long, more than ½ of total length. Anterior angles projecting, obtuse, with blunt tips. Scutellum. Triangular, smooth, shiny, impunctate. Elytra. Surface glossy black, rugo punctate at anterior region, near base coarser; punctate surface extending for 12 mm. in length, almost 1/5 of L. Elytral pilosity very uniform, yellowish-brown, with easy detectable longitudinal ridges, three or more for each elytron, almost equidistant. Dorsal longitudinal and lateral edges glossy black, vith very fine punctuation. Pygidium. In lateral view, concave, with very fine punctuation. Surface in basal half covered with short, fine, greyish pubescence; in apical half with scattered, erected brown-yellowish setae. Abdomen. Sternites very finely punctate, covered by short, yellowish-brown pilosity, except for a small central portion in the middle of sternites III-IV-V. Legs. Protibiae shorter than tarsi, shorter than in the males, tarsi shorter too; FL mm. 17, TF mm. 20. External sides with three strong teeth almost equidistant. The basal and the subapical teeth almost equal in length; the apical tooth smaller. Inner side without a strong dilatate apex. Inner spur curved ventrally and shorter than apical tooth. On mesotibiae and metatibiae three lateral sharp teeth, with the subapical and the apical weakely evolving in lateral carinae, with presence of basal embrional spinous processes.
The subspecies penyai is restricted to an area in Central-Western Paraguay (Holotype from Loma Plata, Chaco). The main distinctive characters differentiating it from the subspecies joergenseni are found mainly in the smaller medial thoracic horn and in the denser pubescence, giving a more brownish color. It is also usually smaller than ssp. joergenseni. (Figs 27A-B, courtesy Mushisha). It is interesting to note that in the first two Brazilian States, namely in the region of Teresópolis, RJ, it is syntopic with Megasoma typhon typhon. The distinctive characters are the cephalic horn and the sickle-shaped thoracic horn both are short with a very wide bifurcated apex. Total body length ranges from 50 to 90 mm. (Figs 28A-B), courtesy Mushisha). The distribution range of this species (Northern Brazil, border with Venezuela and Guyanas) represents the northernmost distribution compared to the aforementioned species and subspecies. It is likely that Endroedi's (1977) and  claims on the alleged presence of M. gyas in Suriname and Guyana, refer to this species. The validity of this taxon has been recently confirmed by further findings from Venezuela, at the border with Brazil (see Kobayashi 2019). A large specimen of M. hermes is deposited in the Collection of MSNM. It is a completely glabrous Megasoma on its dorsal side. Ventrally it bears sometimes a very poor pubescence, mainly on female specimens. The variability of total body length ranges from 68 to 105 mm. (Figs 29A-B, courtesy Mushisha). Only ten specimens have been collected thus far.   Table 2A  Table 2B   Table 2c  Table 2d Table 2E