Sylvicanthon edmondsi, 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 : 131-135

Sylvicanthon edmondsi sp. nov.

urn:lsid:zoobank.org:act:6C7F8A07-DAB4-4CB9-B0BA-D7CF986C19F5

Figs 11I , 13F , 15K , 18C , 20 , 34 , 38 A–B

Sylvicanthon sp. 1 – Celi et al. 2004: 46.

Sylvicanthon cf. bridarolli [sic] – Noriega et al. 2008: 79 (tentative association).

Etymology

A tribute to the great American scarabaeidologist W.D. Edmonds, a student of the tribe Phanaeini and author of some of the major classics on the biology and morphology of Scarabaeinae . In recognition of his very kind support and continuous encouragement to MC since their very first contact. The holotype of S. edmondsi sp. nov. is deposited in the TAMU collection, the institution where the formerly private Edmonds collection is now housed ( Streit 2012). The specific name is a noun in the genitive case.

Material examined

Holotype

ECUADOR: ♂, Orellana, Parque Nacional Yasuní, Estación Científica Yasuní , 215 m (“ ECUADOR: Napo Prov. / Estación Cientifica Yasuní / IX-5-10- 1999, 215 m / Coll. E. G. Riley ”, “TAMU-ENTO / X0668859 / [código de barras]”) ( TAMU).

Paratypes (42 ♂♂, 43 ♀♀)

COLOMBIA: Amazonas: 1 ♂, 1 ♀, Leticia, Parque Nacional Natural Amacayacu, Dec. 1998, J. Noriega leg. ( CPJN). – Caquetá: 1 ♀, Parque Nacional Natural Sierra de Chiribiquete, 300 m, Feb. 2000, pitfall with human faeces, J. Noriega leg. ( CPJN).

ECUADOR: Morona Santiago: 5 ♂♂ (1 dissected), 2 ♀♀, Untsuants, sítio 3, 700 m, 13 Jan. 2002, pitfall with human faeces, J. Celi and M. Ortega leg. ( CMNC). – Orellana: 1 ♂, Parque Nacional Yasuní, Estación Científica Yasuní, 00º38′ S, 76º36′ W, 215 m, 27. Jul.–1 Aug. 1998, pitfall with human faeces, Ratcliffe, Jameson, Smith and Villatoro leg. ( CMNC); 29 ♂♂ (2 dissected), 32 ♀♀, Parque Nacional Yasuní, Estación Científica Yasuní, 215 m, 5–10 Sep. 1999, E.G. Riley leg. ( TAMU); 1 ♂, Parque Nacional Yasuní, Estación Científica Yasuní, 9–17 Sep. 1999, D.G. Marqua leg. ( TAMU); 1 ♂, Parque Nacional Yasuní, via Maxus km “Onkone Gare”, 220 m, 14 Nov. 2001, canopy fogging, P. Araujo leg. ( CEMT); 2 ♂♂, 1 ♀, Rodrigo Borja, IAMOE, 4 Jun. 2000, pitfall with human faeces, A. Dávalos leg. ( CEMT); 1 ♂, Tiputini Biodiversity Station, 0º38′ S, 76º09′ W, 220 m, sep. 2000, carrion trap, D. Inward leg. ( BMNH); 2 ♀♀, Tiputini Biodiversity Station, Río Tiputini, 0º40.5′ S, 76º24′ W, Jul. 1999, flight interception trap, A. Tishechkin leg. ( CEMT).

PERU: Junín: 1 ♂, Satipo, Oct.–Nov. 2002 ( CEMT). – Loreto: 3 ♀♀, Campamento San Jacinto, 02º18′44.85″ S, 75º51′46″ W, 175–215 m, 3–12 Jul. 1993, flight interception trap, R. Leschen leg. ( CMNC); 1 ♀, Río Pucacuro, 203 m, 21 Nov. 2007, dung pitfall, Cesar Moreno leg. ( CEMT).

Description

COLOURATION. Entire body with very dark tonalities. Head dark purple (in some specimens, frons with greenish reflections). Pronotum with strong greenish or bluish sheen at centre and purplish reflections on sides. Elytra usually dark blue or purple, occasionally with weak greenish reflections; striae with same colouration as the rest of tegument and not contrasting with it. Metaventrite black with very weak greenish or coppery shine. Meso- and metafemora orange-brown or yellowish, with base distinctly darker than at least apical two-thirds. Pygidium usually with predominant greenish shine and some coppery reflections, especially at base.

HEAD. Tegument little shiny, with strong alveolar microsculpture obliterating almost completely micropunctation, which is almost imperceptible or even absent throughout outer edge of head. Clypeus with two apical teeth obtuse and only slightly separated from one another; with single transverse row of setae covering base of both teeth. Genae with strong tooth immediately behind clypeal-genal juncture. Posterior edge of head completely unmargined.

THORAX. Pronotum with tegument slightly bright and lustrous, with very fine microsculpture (sometimes absent at centre), and dense, clearly marked central micropunctation. Posterior edge with fine transverse line at centre (usually extending only up to second elytral stria). Hypomeral cavity entirely glabrous or at most with very few short setae at centre; long setae, if present, restricted to anterior and posterior regions ( Fig. 35B ); external margin with weak tubercle. Metaventrite entirely glabrous; tegument with strong rivose microsculpture on anterior region and weaker microsculpture adjacent to internal margin of mesocoxae; at centre, alveolar microsculpture very fine and progressively more diffuse and undifferentiated towards posterior region; micropunctation very fine, but always evident.

LEGS. Ventral surface of all femora and tibiae bright. Profemora with tegument with strong rivose microsculpture and without micropunctation. Protibiae narrow and with internal edge straight and simple, without expansion; at apical third, with three acute teeth, two apical ones of subequal length and larger than basal ( Fig. 11I ). Mesofemora margined anteriorly only at their basal half; unmargined portion of anterior edge with row of very short setae; posterior margin absent; tegument with effaced rivose microsculpture. Metafemora margined anteriorly, posterior margin absent; apical half of anterior edge covered by row of setae; tegument covered by diffuse rivose microsculpture and without any trace of coarse punctation at base ( Fig. 13F ). Metatarsomeres II and V subequal in length and longer than the others; metatarsomere IV shorter than the others.

ELYTRA. With at most nine very narrow visible striae: in general, first two to four striae well marked, very finely carinulate, and without basal widening; remaining striae progressively more effaced and interrupted; eighth and ninth only seen in specimens with very well-marked striae and, in these cases, always very subtle; all striae lack carinulae before reaching apex of elytra, where they are completely indistinct; humeral carina absent. Tegument of interstriae with diffuse shine and lustrous, with alveolar microsculpture throughout elytra surface; micropunctation, in general, clearly visible at 20x magnification.

ABDOMEN. Tegument of ventrites I–V with rivose microsculpture, in general, diffuse at centre; ventrite VI with rivose microsculpture very diffuse and micropunctation very subtle; both sexes without lateral foveae. Pygidium with shiny tegument and covered by alveolar microsculpture; micropunctation subtle, but always evident among microsculpture.

AEDEAGUS. Parameres at least half as long as phallobase and asymmetrical: external face of right paramere flat, external face of left paramere concave, strongly excavated. In lateral view, parameres with ventral keel ( Fig. 18C ).

SEXUAL DIMORPHISM. Males: Protibial spur narrow and bifid at apex, with spiniform projections, the external projection much longer than the internal one ( Fig. 15K ). Ventrite VI with posterior edge strongly narrowed at centre; anterior edge covered only very slightly by weak medial flange of ventrite V. Females: Protibial spur simple, spiniform. Ventrite VI very broad at centre; anterior edge covered by weak medial flange of posterior edge of ventrite V.

Measurements

Males (N =10). TL: AV: 7.0 ± 0.70; MX: 8.0; MN: 6.1. EW: AV: 5.3 ± 0.42; MX: 5.7; MN: 4.3. PrL: AV: 2.3 ± 0.10; MX: 2.5; MN: 1.8. PrW: AV: 4.5 ± 0.36; MX: 4.9; MN: 3.7. PgL: AV: 1.4 ± 0.12; MX: 1.5; MN: 1.1. PgW: AV: 2.2 ± 0.17; MX: 2.3; MN: 1.8.

Females (N = 12). TL: AV: 7.2 ± 0.49; MX: 8.0; MN: 6.4. EW: AV: 5.2 ± 0.30; MX: 5.7; MN: 4.7. PrL: AV: 2.3 ± 0.19; MX: 2.6; MN: 2.0. PrW: AV: 4.5 ± 0.26; MX: 4.9; MN: 4.1. PgL: AV: 1.3 ± 0.10; MX: 1.4; MN: 1.1. PgW: AV: 2.2 ± 0.17; MX: 2.5; MN: 1.9.

Geographical distribution

Northwestern Amazonia, mainly in Sub-Andean areas in Colombia, Ecuador, and Peru.

Ecoregions

Napo Moist Forests , Cordillera Oriental Montane Forests, Peruvian Yungas.

Collecting sites ( Fig. 34 )

COLOMBIA. Caquetá: Parque Nacional Natural Sierra de Chiribiquete. Amazonas: Leticia (Parque Nacional Natural Amacayacu).

ECUADOR. Orellana: Parque Nacional Yasuní, Tiputini Biodiversity Station. Morona Santiago: Untsuants.

PERU. Loreto: Campamento San Jacinto. Junín: Satipo.

Intraspecific variation and taxonomic discussion

Sylvicanthon edmondsi sp. nov. is an interesting case of a species easily recognizable at first glance by its darker colouration ( Fig. 38A ), its very subtle elytral striae, and its smaller size, but that does not have any exclusive morphological character, as the shape of the parameres or a specific micropunctation or microsculpture pattern, that could differentiate it from the other species in a more objective way. Along with S. seag sp. nov. and S. attenboroughi sp. nov., S. edmondsi sp. nov. is distinguished very easily from S. bridarollii by the shape of the parameres: in lateral view, a strong ventral keel is seen in S. edmondsi sp. nov. ( Fig. 18C ), while the parameres are simple in the latter species ( Fig. 18A ); besides, the parameres’ external faces are asymmetrical in S. edmondsi sp. nov. (left paramere with external face excavated and right paramere flat), while they are symmetric (both faces flat) in S. bridarollii . Furthermore, S. edmondsi sp. nov. distinguishes itself from S. bridarollii by the tegument at the centre of the pronotum, which shows a fine, sometimes smoothed microsculpture, and a very dense, clearly marked micropunctation; by the absence of long setae at the centre of the hypomeral cavity ( Fig. 35 A– B); metaventrite with a very fine microsculpture at the centre; and the shape of the protibiae ( Fig. 11I ). From S. attenboroughi sp. nov. and S. seag sp. nov., S. edmondsi sp. nov. differs simultaneously by head with micropunctation almost imperceptible and hypomeral cavity not as strongly excavated as in the first two species; from S. seag sp. nov., in particular, S. edmondsi sp. nov. is different mostly because of the shape of the protibial spur ( Fig. 15K ), the shape of the anterior margin of the female ventrite VI, and the shape of the parameres ( Fig. 18C ). See Table 4 for a detailed comparison between S. edmondsi sp. nov. and the other species of the bridarollii subgroup.

The distribution of S. edmondsi sp. nov. is the most limited in the bridarollii subgroup: this species is present in the humid forests on the slopes of the Andes, in altitudes between 200 and 1110 m, from Colombia in the north to Peru in the south ( Fig. 34 ). We have not seen any geographical variation among the studied populations.

Comments

It was possible to verify that the morphotype named “ Sylvicanthon sp. 1” by Celi et al. (2004) is, in fact, S. edmondsi sp. nov. because we examined some of the specimens collected by them (which are now housed at the CMNC) and found the following results: six specimens of S. edmondsi sp. nov. from site (“ Sítio ”) 3 (700 m); three specimens of S. bridarollii from site 1 (700 m), one from site 3 (700 m), four from site 5 (600 m) and seven from site 6 (600 m); and a male S. genieri sp. nov. from site 4 (1100 m) and three others from site 7 (900 m). Table 3 of Celi et al. (2004) shows that what they called S. bridarollii was collected between 500 and 900 m, “ Sylvicanthon sp. 1”, between 600 and 1110, and “ Sylvicanthon sp. 2”, between 600 and 1300 m. Putting all these data together, we conclude that the specimens of S. bridarollii were correctly identified by Celi et al. (2004), while morphotypes “ Sylvicanthon sp. 1” and “ Sylvicanthon sp. 2” refer, respectively, to S. edmondsi sp. nov. and S. genieri sp. nov.

Natural history

Label information tell us that adults of S. edmondsi sp. nov. are active at least between June and January (during that period, no records only from October and December). Specimens were collected mostly in pitfall traps baited with human faeces, but a male from the Tiputini Biodiversity Station (Morona Santiago, Ecuador) was attracted to carrion. Another male was collected at the Parque Nacional Yasuní (Orellana, Ecuador) by the canopy fogging method, but there are no data as to the height of the trees. As for the altitudinal amplitude, studied specimens were collected between 200 and 700 m; in Morona Santiago, Celi et al. (2004) collected 116 specimens between 600 and 1110 (cited as “ Sylvicanthon sp. 1”; see the discussion of S. bridarollii for details on the sympatry between that species and S. edmondsi sp. nov.).

Figures

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. 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. 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. 18. Aedeagus morphological diversity in the bridarollii subgroup.A. S. bridarollii (Martínez, 1949). B. S. seag sp. nov. (arrow points to the ventral notch). C. S. edmondsi sp. nov. (idem). D. S. attenboroughi sp. nov. (idem).

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. 34. Distribution of the four species of the bridarollii subgroup.

Fig. 38. A–B. Sylvicanthon edmondsi sp. nov. A. Dorsal view. B. Ventral view. C–D. Sylvicanthon attenboroughi sp. nov. C. Dorsal view. D. Ventral view.

Fig. 35. Variation on the pilosity at the centre of the hypomeral cavity among members of the bridarollii subgroup. A. Sylvicanthon seag sp. nov. B. S. attenboroughi sp. nov. C–D. S. bridarollii (Martínez, 1949). Note the first two species have the hypomeral cavity entirely glabrous or with setae limited to its periphery (centre always glabrous), whereas S. bridarollii possesses long and dense setae throughout the tegument of the hypomeral cavity.