Streblopus punctatus ( Balthasar, 1938 )

Cupello, Mario, Ribeiro-Costa, Cibele S. & Vaz-De, Fernando Z., 2020, Systematics of the enigmatic South American Streblopus Van Lansberge, 1874 dung beetles and their transatlantic origin: a case study on the role of dispersal events in the biogeographical history of the Scarabaeinae (Coleoptera: Scarabaeidae), European Journal of Taxonomy 603, pp. 1-85: 38-46

publication ID

https://doi.org/10.5852/ejt.2020.603

publication LSID

lsid:zoobank.org:pub:618B3AFF-6EA5-4803-BA7B-A3446CEF3F85

DOI

http://doi.org/10.5281/zenodo.3671774

persistent identifier

http://treatment.plazi.org/id/D651F73D-6C7A-FFF7-FDE0-D96C1758F9A6

treatment provided by

Plazi

scientific name

Streblopus punctatus ( Balthasar, 1938 )
status

 

Streblopus punctatus ( Balthasar, 1938)  

Figs 3–4 View Fig View Fig , 5 View Fig C–D, F, 6B, 7B, 8C–D, 12B, 13E–F, 14C–D, 15C–D, G–H, 16B–C, 17C–F, 18C–D, 19D–E, 20C–D, 21C, E, 23E–H, 25, 26B, 27B–D, 28

Streblopoides punctatus Balthasar, 1938: 216   .

Streblopoides punctatus ‒ Balthasar 1941: 346   ; 1951: 331. — Vulcano & Pereira 1964: 580–581. — Bezděk & Hájek 2011: 374 View Cited Treatment .

Streblopoides punctata ‒ Blackwelder 1944: 203   .

Streblopoides? punctatus ‒ Krajcik 2006: 163   .

Streblopus punctatus ‒ Halffter & Martínez 1966: 153–154   , 157–158, 162–165, figs 18–21. — Horgan 2005a: 131; 2005b: 609–610; 2006: 364; 2009: 3529, 3538. — Bezděk & Hájek 2011: 374. — Carvajal-López et al. 2011: 316. — Carvajal-López 2012: 195–197, 199, figs 1–2. — Krajcik 2012: 249. — Ratcliffe et al. 2015: 196. — Chamorro et al. 2018: 85, 98, fig. 8c; 2019: 234 ‒ 235, 313, fig. 50d. — Cupello & Vaz-de-Mello 2019: 168 ‒ 169.

Streblopus opatroides   (error) ‒ Paulian 1939: 27 (in part: specimen from Oxapampa, Peru).

Material examined

Holotype

PERU? • ♀; dubious provenance [label indicates Peru, Piura, Huancabamba, 3000 m a.s.l., but this does not seem to be precise; see comments below] (“ punctatus   / m.” [Balthasar’s handwriting], “ genotyp / stv. [?] punctatus   / n. sp. / Dr. V. Balthasar det.” [Balthasar’s handwriting], “TYPUS”, “Huancabamba / N.Peru, 3000 m / H. Rolle.”, “ HOLOTYPE ♀ / Streblopoides punctatus   / Balthasar, 1938 / Labelled by Cupello, 2019 ” [MC’s handwriting]); NMPC.

Other material (24 ♂♂, 16 ♀♀)

ECUADOR – Zamora-Chinchipe • 1 ♂, 1 ♀; Refugio de Vida Silvestre El Zarza, Campamento Las Peñas , “Parcela 5”; 1536 m a.s.l.; 9 Sep. 2012; William Chamorro leg.; pitfall baited with human faeces   ;

CEMT • 1 ♀ (antennae, mouthparts, left posterior wing and genitalia dissected); Refúgio de Vida Silvestre El Zarza, Campamento Las Peñas (“C. Las Peñas”), “via a P4”; 1533 m a.s.l.; 11 Sep. 2011; William Chamorro leg.; pitfall baited with human faeces; CEMT • 1 ♂ (genitalia dissected), 1 ♀ (left posterior wing and genitalia dissected); Yantzaza; 1433 m a.s.l.; 11 Dec. 2010; T. Ghia leg.; pitfall baited with human faeces; CEMT.

PERU – Cuzco • 1 ♂; La Convención, Echarate, Comunidad Campesina Santa Rosa (“CC. Santa Rosa ”); 12°33′54.41″ S, 73°05′36.85″ W; 1747 m a.s.l.; 26–29 Jan. 2010; C. Carranza and C. Rossi leg.; MUSM GoogleMaps   . – Junín • 3 ♂♂; Chanchamayo, Chanchamayo, Nueva Italia , Santuario Nacional Pampa Hermosa ; 10°59′52.7″ S, 75°25′34.4″ W; 1737 m a.s.l.; 30 May 2011; D. Silva leg.; MUSM GoogleMaps   1 ♂ (genitalia dissected); same collection data as for preceding; ex W.D. Edmonds collection; TAMU GoogleMaps   2 ♂♂; Chanchamayo, Chanchamayo, Nueva Italia , Santuario Nacional Pampa Hermosa ; 10°59′51.8″ S, 75°25′35.9″ W; 1879 m a.s.l.; 30 May 2011; D. Silva leg.; MUSM GoogleMaps   1 ♂; same collection data as for preceding; ex W.D. Edmonds collection; TAMU GoogleMaps   1 ♀ (genitalia dissected); Chanchamayo, Chanchamayo, Nueva Italia , Santuario Nacional Pampa Hermosa ; 10°59′51.8″ S, 75°25′35.9″ W; 1940 m a.s.l.; 23–31 May [201?]; M. Alvarado leg.; Podocarpus   forest; MUSM GoogleMaps   1 ♀; Chanchamayo, San Ramón ; 11°10′ S, 75°18′ W; 1500 m a.s.l.; 25 Aug. 2002; F.G. Horgan leg.; forest; pitfall with human faeces; MUSM GoogleMaps   1 ♂ (genitalia dissected); Satipo ; 600 m a.s.l.; 23 May–3 Jun. 2004; A. Santibañez leg.; CEMT   1 ♂ (genitalia dissected), 1 ♀ (genitalia dissected); Satipo ; 1100 m a.s.l.; Dec. 2004; A. Santibañez leg.; CEMT   1 ♀; Satipo ; 1100 m a.s.l.; Dec. 2004; A. Santibañez leg.; MNHN   1 ♀ (genitalia dissected); Satipo, Río Venado ; Feb. 2011; CEMT   2 ♂♂ (1 with genitalia dissected), 3 ♀♀ (1 with genitalia dissected); Satipo , “near [city of] Satipo”;> 1000 m a.s.l.; Dec. 2004; A. Santibañez leg.; yungas; trap with human faeces; ex W.D. Edmonds collection; TAMU   . – Pasco • 2 ♂♂ (1 with genitalia dissected), 1 ♀; Oxapampa, Villa Rica, Bosque de Protección de San Matías-San Carlos ; 10°38′51″ S, 75°12′22″ W; 1556 m a.s.l.; 3–5 May 2012; L. Figueroa and V. Borda leg.; pitfall with dung; MUSM GoogleMaps   3 ♂♂, 3 ♀♀ (1 with genitalia dissected); Oxapampa, Villa Rica, Bosque de Protección de San Matías- San Carlos ; 10°38′44″ S, 75°12′37″ W; 1596 m a.s.l.; 6–10 Aug. 2012; P. Sanchez and E. Razuri leg.; MUSM GoogleMaps   1 ♂; Oxapampa, Villa Rica, Bosque de Protección de San Matías-San Carlos ; 10°36′27″ S, 75°12′18″ W; 1627 m a.s.l.; 3–5 May 2012; L. Figueroa and V. Borda leg.; pitfall with dung; MUSM GoogleMaps   4 ♂♂ (1 with genitalia dissected), 1 ♀; Oxapampa, Villa Rica, Bosque de Protección de San Matías-San Carlos ; 10°38′44″ S, 75°12′37″ W; 1702 m a.s.l.; 3–5 May 2012; L. Figueroa and V. Borda leg.; pitfall with dung; MUSM GoogleMaps   .

Erroneous record

PERU • 1 ♀; Lima; Sep. 1949; ex Martínez collection; CMNC   .

Not studied (label information provided by François Génier (CMNC); 2 ♀♀)

PERU • 1 ♀; Huánuco, Leoncio Prado, La Divisoria (“Divisoria”); 1300 m a.s.l.; Aug. 1974; Bordon leg.; ex Martínez collection; CMNC   .

Etymology

Derived from the Latin word for punctate ( Brown 1956), a probable reference to the fine umbilicate punctation seen on the pronotum of this species.

Redescription

MEASUREMENTS. Males (4 spec.): TL: AV 13.53, MX 14.4, MN 12.45. EW: AV 8.08, MX 8.64, MN 7.04. PW: AV 7.23, MX 8.06, MN 6.51. – Females (5 spec.): TL: AV 12.96, MX 13.95, MN 12.6. EW: AV 7.71, MX 8.0, MN 7.52. PW: AV 6.88, MX 7.13, MN 6.66.

COLOURATION. Antennal club usually with dark tegument and yellowish pubescence; some individuals with lighter tegument. Dorsum light brown; venter, including legs, dark brown to almost black. Some parts of body, especially elytra, pygidium and outer sides of metaventrite, sometimes with silky reddish sheen.

HEAD. Canthus short, with short penetration into eyes ( Fig. 5F View Fig ). Clypeal process a transverse carina, acuminate at apex ( Fig. 6C View Fig ). Antennae with 8 articles; first visible article of funicle little longer than combined length of second and third visible articles of funicle combined ( Fig. 7B View Fig ). Labrum with anterolateral regions not well projected and with external margin more or less straight; anterior labral margin not broad; epipharynx with short medial brush and median area almost entirely covered by dense, thick socketed setae ( Fig. 8 View Fig C–D).

THORAX. Pronotum with sparse umbilicate punctation at centre (approximately at area between eyes) ( Fig. 12B View Fig ); towards sides and posterior region, punctation progressively denser, but punctures never confluent; tegument between punctures with diffuse microsculpture. Prosternum, mesoventrite, mesanepisterna, metanepisterna and metaventrite entirely covered by sparse umbilicate punctation, particularly sparse and with smaller punctures on anterior lobe and posterior region of metaventrite; tegument between punctures lustrous, with extremely diffuse microsculpture ( Fig. 13 View Fig E–F).

LEGS. Trochantofemoral articulation not produced into spur in either sex. Mesocoxae with few sparse umbilicate punctures and tegument lustrous, covered by diffuse microsculpture. Mesofemora always glabrous on posterior edge of both sexes ( Fig. 17 View Fig C–F; sometimes with a few isolated setae in males); ventral surface covered by small and sparse umbilicate punctures at base and centre, and larger and denser punctures near apex and posterior edge; tegument between punctures lustrous and with extremely diffuse microsculpture, except near posterior edge, which is sexually dimorphic (see below). Mesotibiae with internal edge with a few erect setae, never forming well-defined longitudinal rows in either sex ( Fig. 18 View Fig C–D). Metafemora with sexually dimorphic brush of long setae on posterior edge (see below) ( Fig. 19 View Fig D–E). Metatibiae with ventral surface without umbilicate punctures (Ecuadorian specimens) or with at least some umbilicate punctures along entire tegument (Peruvian specimens); internal edge smooth, without row of sharp teeth at base in both sexes ( Fig. 20 View Fig C–D).

ELYTRA. Striae very fine and sometimes discontinuous, especially those on pseudepipleura and stria VII on disc. Tegument covered by small umbilicate punctures, each puncture glabrous or with short central seta; tegument between punctures with diffuse microsculpture (alveoli sometimes better delimited towards apices). Lateral carina (pseudepipleural carina) smooth, not interrupted by row of umbilicate punctures ( Fig. 21C View Fig ). Apices of elytra strongly deflected downwards; distal calluses strongly projecting ( Fig. 21E View Fig ).

TERMINALIA. Aedeagus: Right paramere with pronounced, broadly rounded apical projection with clear external spine ( Fig. 23 View Fig E–H);in dorsal view, parameres with external edges more or less straight ( Fig. 23E View Fig ); in lateral view, ventral side straight, with no week keel nor inclination ( Fig. 23 View Fig F–G). Internal sac with axial and subaxial sclerites distinct in shape: subaxial sclerite curved apically and surrounding axial sclerite, which is simply curved and shorter than subaxial sclerite ( Fig. 25D View Fig ). – Genital sclerite: Medial sclerotized plate (MSP) well sclerotized and with lateral arches more or less straight, not concave; posterior arms of MSP well developed and separated from one another by a deep ‘U-shaped’ emargination ( Fig. 26B View Fig ). – Spermatheca: Entirely slender and with a pair of apical hooks ( Fig. 27 View Fig B–C).

SEXUAL DIMORPHISM. Male: Clypeus slightly emarginated at apex ( Fig. 5C View Fig ). Metaventrite with excavation on posterior region slightly wider and deeper in males than in females ( Fig. 13E View Fig ). Profemora with anterior margin raised into a single spur ( Fig. 14C View Fig ). Protibiae as described above for genus; protibial spur very short, bent inwardly, acuminate ( Figs 15C, G View Fig , 16C View Fig ). Mesofemora near posterior edge with tegument covered by large umbilicate punctures surrounded by dense alveolar microsculpture ( Fig. 17C, E View Fig ). Metafemora with brush of long setae covering basal two-thirds of posterior edge; posterior edge not crenulate and with small spur bent inwards rising just after trochanter ( Fig. 19D View Fig ). – Female: Clypeus with apical emargination absent or only slightly marked ( Fig. 5D View Fig ). Metaventrite with excavation on posterior region slightly narrower and shallower in females than in males ( Fig. 13F View Fig ). Profemora with anterior margin simple, not raised into spur ( Fig. 14D View Fig ). Protibiae with two apical teeth subequal in length, contiguous at base and apart from basal tooth ( Fig. 15D, H View Fig ); all three lateral teeth (especially two apical ones) more or less directed forwards ( Fig. 15D, H View Fig ); protibial spur bent inwards apically, never bifurcated ( Fig. 15D, H View Fig ). Mesofemora near posterior edge with tegument covered by dense umbilicate punctation and tegument between punctures almost smooth, with very diffuse microsculpture (as rest of tegument of mesofemora) ( Fig. 17D, F View Fig ). Metafemora with brush of sparse, long setae covering approximately basal two-thirds of posterior edge; posterior edge crenulate along brush of setae and devoid of any spur ( Fig. 19E View Fig ).

Distribution

Sub-Andean areas in the Peruvian and Ecuadorian Yungas ( Fig. 4 View Fig ).

Ecoregions. Eastern Cordillera Real Montane Forest and Peruvian Yungas.

Collection sites. Ecuador – Zamora Chinchipe: Cordillera del Cóndor (Sector Colibrí), Refugio de Vida Silvestre ‘El Zarza’, Yantzaza. Peru – Huánuco: Leoncio Prado (La Divisoria); Pasco: Oxapampa (Villa Rica: Bosque de Protección de San Matías-San Carlos); Junín: Chanchamayo (Nueva Italia: Santuario Nacional Pampa Hermosa; San Ramón), Satipo (Satipo); Cuzco: La Convención (Echarate).

Intraspecific variation

Until fairly recently, only two specimens of S. punctatus   were known to entomologists, the holotype female housed in the NMPC and another female deposited in the MNHN, both collected in Peru. Over the past two decades, however, with the growing interest for dung beetle studies among South American scholars and the subsequent increase in the number of collections in regions hitherto unexplored in terms of their scarabaeine fauna, that number has risen significantly. For this paper, we were able to examine 43 specimens (24 males and 19 females, including the holotype) deposited in five museums, but we know that some additional individuals are housed in at least two other collections in Ecuador (the Escuela Politécnica Nacional, Quito, and the Museo de Zoología de la Universidad Técnica Particular de Loja, Loja; Carvajal-López 2012; Chamorro et al. 2019). While still not a huge sample, these specimens reveal that S. punctatus   shows some noticeable morphological variation, one of them being clearly geographical.

Firstly, two individuals, a Peruvian male and an Ecuadorian female, possess an antennal club with the tegument considerably lighter than on the other specimens examined, therefore departing from the typical dark tegument of S. punctatus   and approaching the pattern observed in S. opatroides   , whose antennal club has a yellowish tegument. A more significant variation, however, concerns the metatibial punctation: while all Ecuadorian individuals examined show the ventral surface of the metatibiae to be devoid of umbilicate punctures, all the Peruvian specimens studied by us, including the holotype, have at least some sparse umbilicate punctures along their entire ventral surface. However, since all the Peruvian individuals we had the chance to see came from much further south in Peru than its border with Ecuador, we cannot tell exactly how one form replaces the other over the distribution of S. punctatus   , i.e., whether the transition between them is smooth or abrupt. Unfortunately, Carvajal-López (2012), who redescribed S. punctatus   based on a female collected in the Cordillera del Cóndor, on the border between Ecuador and Peru, did not comment on what the tegument of the metatibiae of his specimen was like. As mentioned above for the colour variation observed in S. opatroides   , future collections will give us more detail on how this variation occurs in nature and whether intermediate populations show intergradation between the two forms seen here. As for many other characters showing geographical variation in dung beetle species, nothing is known about the functional role of the umbilicate punctures of the metatibiae in this species, although it is reasonable to suppose they perform some kind of tactile or chemical function. Why this should vary geographically, however, remains totally unknown.

A final variation observed among the specimens is clearly non-genetic: two Peruvian males lack the protibial spur, but it is evident that this condition is due to wear, because one of them has a very short indication of a right spur, which is clearly reduced due to abrasion. As will be discussed on the following pages, in S. opatroides   the protibial spur is never expressed in males, being restricted to females in that species.

Remarks

The information on the presence of S. punctatus in Cordillera   del Cóndor (Zamora Chinchipe, Ecuador) is based on Carvajal-López (2012), who collected a female at 1446 m a.s.l. in that mountain range using a pitfall trap. Conversely, we question two other geographical records present in the literature. First, the type locality mentioned by Balthasar (1938) and indeed stated on the holotype’s label – namely, some place at about 3000 m a.s.l. in the province of Huancabamba (Piura, Peru) – is probably incorrect, since no other specimens are know to have been collected either above ~ 1950 m a.s.l. or in the Páramo ecosystem. Likewise, the record in Halffter & Martínez (1966) of S. punctatus   from the outskirts of Lima (“arredores de Lima ”) is also most probably erroneous, since no other individuals are known from the west side of the Andes nor from the Sechura Desert ecoregion. Luis Figueroa (pers. comm. to MC, 23 Sep. 2018), the Coleoptera   curator at the MUSM and specialist in Peruvian dung beetles, agrees that both records are inaccurate.

Ecology

Like its congeneric S. opatroides   , almost nothing is known about the biology of S. punctatus   . The specimens studied here were collected in both forest fragments and continuous forests at altitudes between 600 and 1940 m, and the holotype is labelled as having been collected at 3000 m (but see comments above about the accuracy of this record). The species is attracted to pitfall traps baited with human and pig excrement ( Horgan 2005a, 2005 b, 2006, 2009; Carvajal-López 2012; Chamorro et al. 2019; data from specimen labels), and adults, like those of S. opatroides   , seem to be active throughout the year, having been recorded in the period “May–June” and all individual months from August to February ( Carvajal-López 2012; Chamorro et al. 2019; data from specimen labels). Horgan’s classification of S. punctatus   as a roller ( Horgan 2005a) was probably based on inference from its morphology, not on actual observations of the food relocation behaviour of this species. Finally, as discussed above for S. opatroides   , the wide eyes and dull colouration of this species lead us to hypothesize that flight activity in S. punctatus   is nocturnal.

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Coleoptera

Family

Scarabaeidae

Genus

Streblopus

Loc

Streblopus punctatus ( Balthasar, 1938 )

Cupello, Mario, Ribeiro-Costa, Cibele S. & Vaz-De, Fernando Z. 2020
2020
Loc

Streblopoides? punctatus ‒

Krajcik M. 2006: 163
2006
Loc

Streblopus punctatus ‒ Halffter & Martínez 1966: 153–154

Cupello M. & Vaz-de-Mello F. Z. 2019: 168
Chamorro W. & Marin-Armijos D. & Granda V. & Vaz-de-Mello F. Z. 2018: 85
Ratcliffe B. C. & Jameson M. L. & Figueroa L. & Cave R. D. & Paulsen M. J. & Cano E. B. & Beza-Beza C. & Jimenez-Ferbans L. & Reyes-Castillo P. 2015: 196
Carvajal-Lopez V. 2012: 195
Krajcik M. 2012: 249
Bezdek A. & Hajek J. 2011: 374
Carvajal-Lopez V. & Villamarin S. & Ortega A. M. 2011: 316
Horgan F. G. 2009: 3529
Horgan F. G. 2006: 364
Horgan F. G. 2005: 131
Horgan F. G. 2005: 609
Halffter G. & Martinez A. 1966: 153
1966
Loc

Streblopoides punctata ‒

Blackwelder R. E. 1944: 203
1944
Loc

Streblopoides punctatus ‒

Bezdek A. & Hajek J. 2011: 374
Vulcano M. A. & Pereira F. S. 1964: 580
Balthasar V. 1951: 331
Balthasar V. 1941: 346
1941
Loc

Streblopus opatroides

Paulian R. 1939: 27
1939
Loc

Streblopoides punctatus

Balthasar V. 1938: 216
1938