Research Article |
Corresponding author: Fernando A. B. Silva ( fernandoabsilva@yahoo.com.br ) Academic editor: Andrey Frolov
© 2019 Fernando A. B. Silva, François Génier.
This is an open access article distributed under the terms of the CC0 Public Domain Dedication.
Citation:
Silva FAB, Génier F (2019) A new Peruvian species of Scybalocanthon Martínez, 1948 (Coleoptera, Scarabaeidae, Scarabaeinae, Deltochilini) and some remarkable intrapopulational variation in the endophallus of S. pinopterus (Kirsch, 1873). ZooKeys 884: 69-80. https://doi.org/10.3897/zookeys.884.39322
|
Scybalocanthon ashei sp. nov. from Madre de Dios, Peru, is described based on differences in external and male genital morphology. Its diagnostic characters and an updated identification key to the species of the genus are provided as well as new distributional data for the following species: S. acrianus Silva & Valois, 2019, S. aereus (Schmidt, 1922), S. kaestneri (Balthasar, 1939) and S. pinopterus (Kirsch, 1873).
Dung beetles, neotropical fauna, taxonomy
The genus Scybalocanthon Martínez, 1948 comprises species distributed from Costa Rica to northern Argentina (
According to the current definition of the genus, Scybalocanthon is characterized by the first meso- and metatarsomeres with external margin with one-half the length of the second tarsomeres, and with apex obliquely truncated; lateral borders of tarsomeres parallel, forming a continuous border for all tarsomeres; overall shape of tarsomeres 2‒4 square to rectangular; and dorsal surface of mesotibiae with dense, randomly distributed setae (
Examination of the collection at the Canadian Museum of Nature (
The material studied was deposited in the following collections:
Examination of the aedeagus and endophallic sclerites allowed clarifying the differences between species. In describing these structures, we followed
Images of specimens and key characters were taken with Leica stereomicroscope M205A, using image stacking software (Leica Application Suite, version 3.7.0), and they were edited using Adobe Photoshop CS4.
Holotype. PERU: MADRE DE DIOS, Reserva Cuzco Amazonica, 15 km NE Puerto Maldonado, 69°03'W, 12°33'S, 200m, 4.VII.1989, Ashe and Leschen legs (1♂
Specimens of Scybalocanthon ashei sp. nov. (Fig.
Scybalocanthon ashei sp. nov. A Holotype (
Species of Scybalocanthon, dorsal views. A S. acrianus B S. adisi C S. aereus D S. arnaudi E S. chamorroi F S. federicoescobari G S. kaestneri (specimen from Pastaza, Ecuador) H S. kaestneri (specimen from Napo, Ecuador) I S. martinezi J S. papaxibe K S. pinopterus (specimen from Madre de Dios, Peru) L S. pinopterus (specimen from Tingo Maria, Huanuco, Peru) M S. pinopterus (specimen from Orellana, Ecuador) N S. pygidialis O S. uniplagiatus, Scale bars: 2 mm.
Aedeagus, detail of parameres in left and right view. A S. acrianus B S. adisi C S. aereus D S. arnaudi E S. chamorroi F S. federicoescobari G S. kaestneri (specimen from Pastaza, Ecuador) H S. kaestneri (specimen from Napo, Ecuador) I S. martinezi J S. papaxibe K S. pinopterus (specimen from Madre de Dios, Peru) L S. pinopterus (specimen from Tingo Maria, Huanuco, Peru) M S. pinopterus (specimen from Tingo Maria, Huanuco, Peru) N S. pinopterus (specimen from Orellana, Ecuador) O S. pygidialis P S. uniplagiatus, Scale bars: 0.5 mm.
Body
: Oval-elongated (Fig.
Named in honor of the late James S. Ashe, collector of most of the known specimens.
Amazon rainforest. Known from Peru (Fig.
According to aedeagus characters, S. ashei sp. nov. (Fig.
1 | Femora completely black. (Scybalocanthon aereus (Schmidt, 1922) (in part), Scybalocanthon maculatus (Schmidt, 1920), and Scybalocanthon kelleri Pereira & Martínez, 1956) |
See |
– | Femora bicolored, central portion pale yellow, with dark spots at least on the tips (Fig. |
2 |
2 (1) | Pronotum with a longitudinal dark band on midline |
See |
– | Pronotum uniformly colored or, if bicolored, lacking longitudinal dark band on midline | 3 |
3 (2) | Black spots on the tips of femora covering approximately 1/15 length of femora | 4 |
– | Black spots on the tips of femora covering approximately 1/5 length of femora, central portion with elliptical yellow spot. (Scybalocanthon korasakiae Silva, 2011, Scybalocanthon aereus (Schmidt, 1922) (in part), Scybalocanthon batesi Vaz-de-Mello & Silva, 2017, Scybalocanthon haroldi Silva & Valois, 2019, Scybalocanthon nigriceps (Harold, 1868), Scybalocanthon darlingtoni (Paulian, 1939), Scybalocanthon sexspilotus (Guérin-Méneville, 1855), Scybalocanthon maculatus (Schmidt, 1920), Scybalocanthon trimaculatus (Schmidt, 1922), and Scybalocanthon moniliatus (Bates, 1887)) |
See |
4 (3) | Pronotum with four black spots, two central spots with triangular shape, and one rounded spot on each side (Fig. |
Scybalocanthon kaestneri (Balthasar, 1939) |
– | Pronotum uniformly colored, lacking spots, or with one elliptical spot on the central portion | 5 |
5 (4) | Eighth elytral stria lacking carina at the anterior portion |
See |
– | Eighth elytral stria with very fine and sharp carina at the anterior portion | 6 |
6 (5) | Left paramere lacking acute projection on dorsal margin and lacking bilobate excavation on ventral margin (Fig. |
See |
– | Left paramere with acute projection on dorsal margin and bilobate excavation on ventral margin (Fig. |
7 |
7 (6) | Bilobate excavation of ventral margin of left paramere wide and deep, extending at least one-half of the paramere margin in the lateral view (Figs |
8 |
– | Bilobate excavation of ventral margin of left paramere short, not reaching one-half of paramere margin in the lateral view (Fig. |
See |
8 (7) | Bilobate excavation of ventral margin of left paramere extending about one-half of the paramere margin in the lateral view (Fig. |
Scybalocanthon martinezi Silva & Valois, 2019 |
– | Bilobate excavation of ventral margin of left paramere extending along two-third of the paramere margin (Fig. |
Scybalocanthon ashei sp. nov. |
In addition to those mentioned by
PERU: MADRE DE DÍOS, 15km N.E. Puerto Maldonado, Reserva Cuzco Amazonica, 12°33'S, 69°03'W, 20.VI.1989, 200m, Ashe and Leschen leg. (1♂
Known from Brazil (Acre), Bolivia and Peru (Fig.
In addition to those mentioned by
BRAZIL: AMAZONAS, Vila Nova (1♀
Known from Brazil (Acre, Amazonas, Mato Grosso), Bolivia, and Peru (Fig.
In addition to those mentioned by
ECUADOR: NAPO, P. Misahualli, 18–22.II.1983, 350m, M. Sharkey leg. (1♂
Known from Ecuador (Fig.
In addition to those mentioned by
ECUADOR: ORELLANA, Limoncocha, 10–15.III.1975, J.M. Campbell leg. (1♂ and 1♀
Known from Ecuador and Peru (Fig.
Scybalocanthon now includes 24 valid species. Based on the aedeagus morphology, including endophallic sclerites, two major patterns within the genus are found: slight paramere asymmetry, namely, parameres with similar shape, but slightly different lengths; and parameres strongly asymmetric, with shapes and lengths conspicuously different. The species which have the second pattern also present the dorsal margin of left paramere with a projection (Figs
Some of those species mentioned above have similar external morphology, including similarities with other species with slightly asymmetrical parameres. Characters of external morphology can also vary within the same species, such as body coloration and patterns of spots. Besides, some of these species overlap in their geographical distribution, which makes them difficult to tell apart without examining the male genitalia. According to the general external morphology and close geographical distribution, specimens of S. ashei sp. nov., S. acrianus, S. adisi, S. aereus, S. arnaudi, S. chamorroi, S. federicoescobari, S. martinezi, S. pinopterus, and S. uniplagiatus can be mistaken at first glance. All these species have distributional records in the western/central Amazon (Fig.
Set of bristles and microbristles of endophallus. A S. pygidialis (specimen from Amazonas, Brazil) B S. pygidialis (specimen from Cayenne, French Guiana) C S. pinopterus (specimen from Madre de Dios, Peru) D S. pinopterus (specimen from Tingo Maria, Huanuco, Peru) E S. pinopterus (specimen from Tingo Maria, Huanuco, Peru) F S. pinopterus (specimen from Orellana, Ecuador) G S. kaestneri (specimen from Pastaza, Ecuador) H S. kaestneri (specimen from Napo, Ecuador).
These observations are in agreement with the hypothesis raised by
We thank CAPES/Pro-equipamentos/UFPA, for providing the photographic equipment used. We thank PROPESP/UFPA (PAPQ 01/2019), for supporting the publication of this paper. We also thank the Conselho Nacional de Desenvolvimento Científico e Tecnológico – CNPq for providing research grants for Fernando Silva (444020/2014-4). Fernando Silva is a CNPq fellow.