Sylvicanthon monnei, Cupello & Vaz-De, 2018

Cupello, Mario & Vaz-De, Fernando Z., 2018, A monographic revision of the Neotropical dung beetle genus Sylvicanthon Halffter & Martínez, 1977 (Coleoptera: Scarabaeidae: Scarabaeinae: Deltochilini), including a reappraisal of the taxonomic history of ‘ Canthon sensu lato’, European Journal of Taxonomy 467, pp. 1-205 : 160-163

Sylvicanthon monnei sp. nov.

urn:lsid:zoobank.org:act:045BB71E-7DD7-4EE3-B7AE-E087F656F754

Figs 13C , 19D , 20 , 41 , 43B, E , 44 C–D

Etymology

A tribute to the Uruguayan-Brazilian entomologist Miguel A. Monné, one of the leading specialists in the New World fauna of Cerambycidae and author of the main catalogue of the family’s Neotropical species plus almost 200 papers dealing with longhorn beetle taxonomy. As the first author’s supervisor throughout his entire undergraduation (2009–2013), it was prof. Monné who first opened doors so that he could work as a zoologist. Through his example and inspiration, MC’s taste for taxonomy, zoological nomenclature and history of entomology, as well as his profound respect for all the great synthesizers of scientific knowledge, quickly flourished.

Material examined

Holotype

BRAZIL: ♂, Mato Grosso, Cotriguaçu, Fazenda São Nicolau , 09º51′18″ S, 58º13′22″ W, 200 m (“BRASIL: MatoGrosso.Cotriguaçu, / Faz. São Nicolau. flor.sec. 200m / 9º51′18″ S, 58º13′22″ W. Fezes / hum. X-2009. Vaz-de-Mello”) ( CEMT).

Paratypes (8 ♂♂, 5 ♀♀)

BRAZIL: Mato Grosso: 2 ♂♂, Cotriguaçu, Fazenda São Nicolau, Prainha, 09º51′36″ S, 58º12′53″ W, Oct. 2009, pitfall, F.Z. Vaz-de-Mello leg. ( CEMT); 2 ♂♂, 1 ♀, Diamantino, Fazenda São João, 14º14′10″ S, 56º08′11″ W, 400 m, 11 Jan. 2001, pitfall with dung, Génier & Vaz-de-Mello leg. ( CMNC); 1 ♂, 2 ♀♀, Porto Estrela, ESEC Serra das Araras, Olho d’Água, 14 Oct. 2011, pitfall, M. Gigliotti leg. ( CEMT); 1 ♂, Porto Estrela, ESEC Serra das Araras, Trilha Bocado do José, 15º38′50″ S, 57º12′27″ W, 238 m, 10 Oct. 2011, pitfall, F.Z. Vaz-de-Mello leg. ( CEMT); 1 ♂, Querência, Fazenda São Luiz, 12º39.94′ S, 52º21.85′ W, 14 Jul. 2008, pitfall, R. Andrade leg. ( CEMT); 1 ♂, 1 ♀, Querência, Fazenda São Luiz, 12º39.64′ S, 52º22.74′ W, 17 Jul. 2008, pitfall, R. Andrade leg. ( CEMT). – Pará: 1 ♀, São Félix do Xingu, Pinkaití Reserve, 07º45′ S, 51º57′ W, 12 Nov. 1998, P.Y. Scheffler leg. ( CEMT).

Description

COLOURATION. Head, pronotum, elytra and pygidium predominantly dark green. Metaventrite very dark, black with soft greenish reflections. Meso- and metafemora reddish-brown or dark brown.

HEAD. Tegument shiny, with well-marked micropunctation and weak alveolar microsculpture, in some specimens very effaced or even absent in some parts of head; micropunctation almost imperceptible or absent at apex of clypeus. Clypeus with two apical teeth obtuse and only slightly separated from one another; with single transverse row of short setae covering base of both teeth. Genae with weak denticle immediately behind clypeal-genal juncture. Posterior edge of head unmargined between eyes.

THORAX. Pronotum with shiny tegument with dense micropunctation at centre; towards the sides, micropunctation progressively less well marked, but always present and evident; alveolar microsculpture present only on anterolateral angles and in narrow strip on sides; at centre, tegument smooth. Posterior edge with fine transverse line at centre (usually extending up to second elytral stria) which, occasionally, can be difficult to see. Hypomeral cavity with some long yellowish setae at centre; external edge with weak tubercle. Metaventrite glabrous at centre; sides with few sparse setae near anterior margin of metacoxae ( Fig. 7B ); anterior region of metaventrite with tegument with strong rivose microsculpture; centre and posterior region with dense micropunctation and without microsculpture.

LEGS.Ventral surface of all femora and tibiae bright.Profemora with tegument with sparse micropunctation and without microsculpture at anterior half and with strong rivose microsculpture at posterior half. Protibiae narrow and with distinct expansion on internal edge; at apical third, external edge with three small acute teeth, two most apical ones subequal in length and larger than basal ( Fig. 11E ). Mesofemora margined anteriorly only at basal half; unmargined portion of anterior edge with row of very short setae; posterior margin absent; tegument smooth and with sparse micropunctation, except apical anterior half, which has strong rivose microsculpture. Metafemora margined only anteriorly, posterior margin absent; apical third of anterior edge covered by row of setae; tegument with rivose microsculpture at anterior half and smooth with sparse micropunctation at posterior half; with strong coarse elongate punctation at base ( Fig. 13C ). Metatarsomeres II and V subequal in length and longer than others; metatarsomere IV shorter than others.

ELYTRA. With only seven narrow visible striae: first three or four well marked, finely carinulate, and widened at base; fifth to seventh progressively more effaced and interrupted; all striae lack carinulae before reaching apex of elytra, where they are marked only by microsculpture or completely indistinct; humeral carina absent. Tegument of interstriae shiny, without microsculpture, and with very dense micropunctation.

ABDOMEN. Tegument of ventrites I–IV with strong rivose microsculpture; ventrite VI smooth at centre and with weak rivose microsculpture on sides. Pygidium with bright tegument, without microsculpture, and with dense micropunctation (occasionally, weak microsculpture present on the sides of pygidium).

AEDEAGUS. Parameres longer than half-length of phallobase and without any noticeable asymmetry, with both external faces flat. In lateral view, parameres with apex slightly bifurcate, with inferior branch of bifurcation only very slightly projected and parallel to superior branch; without ventral keel or notch ( Figs 19D , 44 C–D).

SEXUAL DIMORPHISM. Males: Protibial spur broad and bifid, with external projection spiniform and not much longer than internal projection, which is bent and widened ( Fig. 15N ). Abdomen without lateral foveae. Ventrite VI strongly narrowed at centre due to a distinct emargination on posterior edge; anterior edge slightly covered by weak medial flange of posterior edge of ventrite V. Pygidium very long (length between 1.2 and 1.0 mm) and convex; apical margin of pygidium much wider than lateral margins. Females: Protibial spur spiniform. Abdomen with three pairs of transverse foveae located between ventrites I–II, II–III, and III–IV, respectively; foveae not margined by row of long setae ( Fig. 16A ). Ventrite VI very broad at centre, posterior edge straight, without emargination; anterior edge subtly covered by weak medial flange of posterior edge of ventrite V. Pygidium shorter (about 0.9 mm) and flat; apical margin of pygidium only slightly wider than lateral margins.

Measurements

Males (N = 5). TL: AV: 6.6 ± 0.25; MX: 6.8; MN: 6.3. EW: AV: 4.9 ± 0.29; MX: 5.3; MN: 4.6. PrL: AV: 2.2 ± 0.13; MX: 2.4; MN: 2.1. PrW: AV: 4.4 ± 0.21; MX: 4.6; MN: 4.1. PgL: AV: 1.1 ± 0.09; MX: 1.2; MN: 1.0. PgW: AV: 2.2 ± 0.14; MX: 2.4; MN: 2.1.

Females (N = 3). TL: AV: 6.5 ± 0.20; MX: 6.7; MN: 6.3. EW: AV: 4.9 ± 0.28; MX: 5.1; MN: 4.7. PrL: AV: 2.1 ± 0.21; MX: 2.3; MN: 1.9. PrW: AV: 4.1 ± 0.3; MX: 4.4; MN: 3.8. PgL: AV: 0.9 ± 0.0; MX: 0.9; MN: 0.9. PgW: AV: 2.1 ± 0.0; MX: 2.1; MN: 2.1.

Geographical distribution

Southern Amazonia in Brazil.

Ecoregions

Xingu-Tocantins-Araguaia Moist Forests, Madeira-Tapajós Moist Forests, Mato Grosso Tropical Dry Forests, Chiquitano Dry Forests.

Collecting sites ( Fig. 41 )

BRAZIL. Pará: São Félix do Xingu. Mato Grosso: Cotriguaçu, Diamantino, Porto Estrela (Estação Ecológica Serra das Araras), Querência.

Intraspecific variation and taxonomic discussion

The two most closely related species to S. monnei sp. nov. are S. mayri sp. nov. and S. furvus , from which it can be differentiated by the following combination of characteristics: elytral tegument without any alveolar microsculpture among micropunctation (alveolar microsculpture strongly impressed in S. furvus , and diffuse, but still present in S. mayri sp. nov.), parameres with both branches of apical bifurcation only slightly divergent, the inferior branch being straight and little projected ( Fig. 44 C–D) (parameres strongly bifurcate at apex in S. mayri sp. nov. ( Fig. 44 A–B) and S. furvus , with the inferior branch well developed and widely divergent from the superior branch) and distribution in southern Amazonia ( Fig. 41 ) (on the slopes of Andes in Peru and Bolivia for S. furvus and western Amazonia for S. mayri sp. nov.). A detailed comparison between these three species can be found in the discussion of S. furvus and on Table 5.

Two species of Sylvicanthon can be found in sympatry with S. monnei sp. nov.: S. candezei and S. proseni . From the first, S. monnei sp. nov. can be readily distinguished as follows: protibiae tridentate and with a distinct expansion on their internal margin ( Fig. 11E ) (bidentate and straight on its internal margin in S. candezei , Fig. 11J ), females with three pairs of abdominal foveae ( Fig. 16A ) (without foveae in S. candezei ) and parameres, in lateral view, without any notch on its inferior edge ( Figs 19D , 44C ) (with a profound notch on the middle of ventral edge in S. candezei , Fig. 17C ). It is interesting to note that individuals from southern populations of S. candezei , i.e., those that can be in sympatry with S. monnei sp. nov., differ from northern specimens in having elytra without trace of microsculpture in the same way as seen in S. monnei sp. nov.

Comments

The holotype and two paratypes of S. monnei sp. nov. are part of a large series of dung beetles collected during a faunistic survey on the São Nicolau farm (“Fazenda São Nicolau”), in the municipality of Cotriguaçu (Mato Grosso, Brazil), done in two campaigns at the end of 2009; the three type specimens were caught during the first campaign, between the 5 th and 16 th of October. The survey was published by Vaz-de-Mello et al. (2011b), but, curiously, no Sylvicanthon (except S. proseni , then cited in Canthon ) were included in the final list of 118 species present at the farm. Since 2009, three other new species were described from that material: Lobidion punctatissimum Génier, 2010 of Ateuchini (which was recently transferred to Ateuchus by Génier & Cupello 2018), and Deltochilum (Aganhyboma) schefflerorum Silva et al., 2015 and Hansreia peugeoti Valois et al., 2015 both in Deltochilini .

Natural history

The little we know on the biology of S. monnei sp. nov. is thanks to the information contained on specimen labels. Known specimens were collected in pitfall traps baited with human faeces in January, July, October and November. The species is found in altitudes between 230 and 400 m, in both primary and secondary semideciduous forests, but it is probably rare in both habitats.

Figures

Fig. 13. Morphological variation in the metafemora of Sylvicanthon Halffter & Martínez, 1977. A. S. foveiventris (Schmidt, 1920). Note the presence of coarse elongate punctures at the base of the metafemur (arrow) and the tegument without microsculpture. B. S. obscurus (Schmidt, 1920). Observe the tegument entirely covered by coarse non-elongate punctures. C. S. monnei sp. nov. D. S. mayri sp. nov. E. S. furvus (Schmidt, 1920). F. S. edmondsi sp. nov. G. S. bridarollii (Martínez, 1949) (southern populations). H. S. bridarollii (Martínez, 1949) (northern populations). Note the differences in colouration and in the presence of coarse punctation at the base of metafemur in the two ends of the clinal variation observed in S. bridarollii.

Fig. 19. Aedeagus morphological diversity in Sylvicanthon. A. S. securus (Schmidt, 1920) comb. nov. B. S. obscurus (Schmidt, 1920). C. S. furvus (Schmidt, 1920). D. S. monnei sp. nov. E. S. mayri sp. nov.

Fig. 20. Combined distribution of the species of Sylvicanthon in the Neotropical region. Note that the genus occupies the four great areas of tropical humid forest of the American continent: Central American forests, the Choco of the South American northwest, the Amazon Rainforest and the Atlantic Forest. Following the hypothesis of Martínez et al. (1964) that the Amazon Basin was the ancestral area of the Sylvicanthon of the candezei group, three lineages have independently dispersed from there (arrows): that of the ancestors of S. aequinoctialis (Harold, 1868), which, from the Choco, invaded Central America at the pace of the tropical forests’ gradual northwards advance, occurred during the Plio-Pleistocene, and those of the ancestors of respectively S. obscurus (Schmidt, 1920) and S. foveiventris (Schmidt, 1920), which reached the Atlantic Forest through the corridors of humid forests that bridged that biome to the Amazon forest during the wettest periods of the Neogene (see a more detailed discussion in the text).

Fig. 41. Distribution of Sylvicanthon securus (Schmidt, 1920) comb. nov. and the four species of the furvus subgroup.

Fig. 43. The three Amazonian species of the furvus subgroup. A, D. Sylvicanthon furvus (Schmidt, 1920). A. Dorsal view. D. Ventral view. B, E. S. monnei sp. nov. B. Dorsal view. E. Ventral view. C, F. S. mayri sp. nov. C. Dorsal view. F. Ventral view.

Fig. 44. Differences on the parameres of Sylvicanthon mayri sp. nov. and S. monnei sp. nov. (grayish zones represent original membraneous areas). A–B. S. mayri sp. nov. C–D. S. monnei sp. nov. Note that both branches of the apical bifurcation of the parameres of S. mayri sp. nov. are much more divergent than those of S. monnei sp. nov., which makes the internal angle between them more open in the first species (~110º) than in the second (~78º). In the same way, as the inferior branch is much more projected in S. mayri sp. nov. than in S. monnei sp. nov., the angle between the posterior region of that branch and the rest of the paramere is more open in S. monnei sp. nov. (~147º) than in S. mayri sp. nov. (~137º), species that seems to have a strong excavation at this point of the paramere (indicated by red arrow in A).

Fig. 7. Pterothorax, ventrolateral views. A. Sylvicanthon aequinoctialis (Harold, 1868) comb. nov. B. S. obscurus (Schmidt, 1920). C. Canthon xanthopus Blanchard, 1846. Abbreviations: MsC = mesocoxa; MMsC = external margin of mesocoxa; CMtE = centre of metaventrite; LMtE = lateral region of metaventrite; MtC = metacoxa.

Fig. 11. Morphological diversity in the protibiae of Sylvicanthon Halffter & Martínez, 1977. A. S. enkerlini (Martínez et al., 1964) comb. nov. B. S. aequinoctialis (Harold, 1869) comb. nov. C. S. securus (Schmidt, 1920) comb. nov. D. S. obscurus (Schmidt, 1920). E. S. furvus (Schmidt, 1920). F. S. bridarollii (Martínez, 1949) (southern populations). G. S. bridarollii (northern populations). H. S. attenboroughi sp. nov. I. S. edmondsi sp. nov. J. S. candezei (Harold, 1869). Note the variation related to the presence and degree of development of an expansion on the internal edge of protibiae and to the number, size and position of the external teeth.

Fig. 15. Morphological variation and sexual dimorphism in the protibial spur of Sylvicanthon. A. S. enkerlini (Martínez et al., 1964) comb. nov., ♂. B. S. foveiventris (Schmidt, 1920), ♂. C. S. candezei (Harold, 1869), ♂. D. S. genieri sp. nov., ♂. E. S. aequinoctialis (Harold, 1868), ♂. F. S. aequinoctialis comb. nov., ♀. G. S. proseni (Martínez, 1949) stat. et comb. nov., ♂. H. S. proseni stat. et comb. nov., ♀. I. S. bridarollii (Martínez, 1949), ♂. J. S. seag sp. nov., ♂. K. S. edmondsi sp. nov.,♂. L. S. attenboroughi sp. nov., ♂. M. S. obscurus (Schmidt, 1920), ♂. N. S. furvus (Schmidt, 1920), ♂. O. S. securus (Schmidt, 1920) comb. nov., ♂.

Fig. 16. Abdominal lateral foveae of females (arrows). A. Sylvicanthon furvus (Schmidt, 1920). B. S. mayri sp. nov. C. S. obscurus (Schmidt, 1920). D. S. foveiventris (Schmidt, 1920).

Fig. 17. Aedeagus morphological diversity in Sylvicanthon. A. S. enkerlini (Martínez et al., 1964) comb. nov. B. S. foveiventris (Schmidt, 1920). C. S. candezei (Harold, 1869) (arrows points to the ventral notch). D. S. genieri sp. nov. (idem). E. S. aequinoctialis (Harold, 1868). F. S. proseni (Martínez, 1949) stat. et comb. nov.