Plebeia emerinoides (Silvestri)

Roig-Alsina, Arturo & Alvarez, Leopoldo J., 2017, Southern distributional limits of Meliponini bees (Hymenoptera, Apidae) in the Neotropics: taxonomic notes and distribution of Plebeia droryana and P. emerinoides in Argentina, Zootaxa 4244 (2), pp. 261-268 : 264-267

Plebeia emerinoides (Silvestri)

( Figs. 6–14 , 16 )

Trigona emerinoides Silvestri, 1902: 160 –162, figs. 19, 26–28 (Lectotype worker, Santa Ana, Misiones [Argentina], Silvestri leg., Portici. Examined). Camargo & Moure, 1988: 307, figs. 22 and 23 (lectotype designation). Plebeia nigriceps: Moure, 1962: 8 (specimen from S. Anna, Villa Rica, Paraguay, not Trigona nigriceps Friese , misidentification). Camargo & Moure, 1988: 307 (misidentification). Camargo & Pedro, 2007: 465 (specimens from Buenos Aires, misidentification).

Plebeia emerinoides: Alvarez et al., 2016: 72 , 73.

Diagnosis. The worker of Plebeia emerinoides is characterized by the following combination of features: paraocular yellow band reaching at most two thirds of the eye length; the clypeus more or less yellow (see variation below) but always with an apical dark band ( Figs. 6–8 ); the yellow band on the scutum narrow, beginning usually at the anterior level of the tegula; the yellow band on the posterior margin of the scutellum usually interrupted medially ( Fig. 9 ); the sparse punctation of the scutum (punctures between notauli separated by 2 puncture diameters) with shiny integument between punctures; the plumose, branched hairs on the disk of the scutum; and the reduced malar space, 0.4 times the diameter of the third flagellomere. The male is characterized by the shape of the fifth metasomal sternum ( Fig. 12 ), with long, triangular lateral lobes directed posteriorly and bearing very long setae on the outer margin. The sixth metasomal sternum and the genital capsule are as in figures 13 and 14.

Comments. This species has been referred to as " nigriceps " in some recent contributions and catalogs ( Camargo & Moure 1988; Camargo & Pedro 2007), where the name emerinoides has been considered a junior synonym. We contend that this synonymy of emerinoides under nigriceps Friese is unfounded.

Filippo Silvestri collected numerous Meliponini and studied the nests of many of them during his journey to northern Argentina, Paraguay, and Brazil in 1900. Later he published a report of his observations ( Silvestri 1902), including the description of three new species, Trigona emerinoides from S. Ana, Misiones among them.

Camargo & Moure (1988) studied the specimens collected by Silvestri, which are preserved in Portici, Italy. They identified a series of 17 workers and one male as the type series of Trigona emerinoides Silvestri , and designated a worker as the lectotype. The series was labeled "Miri, S. Ana," and " Trigona sp.? bei emerina, 1900, Friese det." Silvestri (1902) stated that the specimens that he was describing as T. emerinoides came from Santa Ana, Misiones, where he studied a nest of this species. Camargo & Moure (1988, p. 293) erroneously attribute the locality Santa Ana to a place in Paraguay. Camargo & Pedro (2007) also cite "Santa Ana, Paraguay" as the type locality. Silvestri (1902), in his contribution on the Meliponini , does not clearly state the country for most of the localities that he mentions, and this is the case for "Santa Ana, Misiones." This brief mention of the type locality may be seen as confusing, because there are both a department of Misiones in Paraguay and a province of Misiones in Argentina, regions that already had these names by 1900. But, in a further contribution on termites, Silvestri (1903, p. 5) lists by country all the localities that he surveyed in South America, including also the dates of visit. From this list it is clear that the type locality of T. emerinoides is Santa Ana, province of Misiones, Argentina ( Fig. 16 ), and that the specimens were collected between June and July of 1900.

This confusion on the locality Santa Ana is connected to a misinterpretation of T. nigriceps Friese. Camargo & Moure (1988, p. 309) suggest that Friese (1901) based Trigona nigriceps on specimens collected by Silvestri. There is no basis for this supposition because Friese (1901) clearly states that the two syntypes of T. nigriceps came from Villarica, Paraguay, collected by Burgdorf (without indication of date) ( Fig. 16 ). In the same paragraph, Camargo & Moure (1988) then discuss a specimen preserved at the Museu de Zoologia in São Paulo (MZSP #96041 with printed label "Villarica, Paraguay, 1900," overwritten by hand "S. Anna") identified by Friese as T. nigriceps , as being possibly one of the two specimens used by Friese in the original description of T. nigriceps . They indicate that the São Paulo’s specimen is identical to those of the type series of T. emerinoides . This specimen had already been studied by Moure (1962, p. 8), who acknowledged that even though it was identified by Friese himself as T. nigriceps , it does not agree with Friese’s description, that clearly states that the two syntypes of T. nigriceps had the face entirely black, with the labrum and mandibles reddish. Contrasting with Friese’s original specimens, the specimen in the Museum of São Paulo bears yellow marks on the clypeus, supraclypeal area, paraocular areas, mandibles, and labrum. Hence, the São Paulo specimen cannot be considered a syntype of T. nigriceps , albeit identified by Friese with this name. Thus, its agreement with the type series of emerinoides does not support the synonymy proposed by Camargo & Moure (1988).

We have not been able to locate the original specimens of T. nigriceps Friese , which seem to be lost. A better study of the local fauna of the Villarica area in Paraguay will help to solve the identity of T. nigriceps . In Argentina, Friese's description would fit the color pattern of Plebeia molesta (Puls) , although the size stated by Friese (3.5 mm long) is rather small for P. molesta , which ranges between 3.8 and 4.5 mm in length. We have not seen any specimens of P. emerinoides with the face entirely black and with reddish labrum and mandibles. On the other hand, we have studied specimens of P. emerinoides from Villarica (43 workers and 15 males, Villarica, Paraguay, 3-II-1946, 8-IV-1947, F. Schade, MLP) and these specimens have a pattern of extensive yellow markings (as in Fig. 6 ) similar to that described by Silvestri and illustrated by Camargo & Moure (1988, figures 22 and 24). We consider T. nigriceps Friese as a species incertae sedis until more information is gathered.

The pale maculations of P. emerinoides vary in extent within and among populations from Argentina. In specimens from the northern province of Misiones the maculations are usually well-developed ( Fig. 6 ), whereas they are reduced in specimens from southern provinces, such as Entre Ríos and Buenos Aires ( Figs. 7 and 8 ). In a series of 55 workers from the same nest (Campo Ramón, Oberá, Misiones) the coloration of the clypeus varies from entirely yellow except for the apical dark band (as in the lectotype, figured by Camargo & Moure 1988) to yellow with a paramedian brown stripe or median spot, or with a brown center margined above and laterally by yellow. This darkening of the center of the clypeus is more pronounced in some specimens from Buenos Aires, in which most of the clypeus is nearly entirely dark brown with a lateral triangular yellow spot at each lower corner (as Fig. 8 ). The paraocular yellow band is always present, but its width varies, being usually less developed in specimens from Entre Ríos and Buenos Aires than in specimens from Misiones. The yellow spot on the supraclypeal area is always present and distinct. This reduction of the yellow color on the face also occurs in males. Specimens from the southern end of the distribution have the clypeus and the under surface of the scape with extended brown areas ( Fig. 11 ). Nevertheless, the sternal and genitalic structures of males from Buenos Aires and Misiones are identical. The pale maculations in the mesosoma vary even among specimens from the same nest. In the series of workers from Campo Ramón, Misiones, the pale band on the posterior margin of the scutellum is usually briefly interrupted medially, but in some specimens it is uninterrupted and in others it is reduced to two yellow spots.

Therefore, we conclude that there is no basis for claiming that P. emerinoides is a junior synonym of T. nigriceps and consequently we maintain here that P. emerinoides is the valid name of the species. This species of Plebeia is widespread in the province of Misiones in Argentina, and is also known from several localities in the provinces of Corrientes and Entre Ríos along the Uruguay River, reaching to the south the northern portion of the province of Buenos Aires ( Fig. 16 ).

Material studied: (597♀ 38♂) ARGENTINA. Buenos Aires ; 6♀, Canal San Fernando , 29-X-1945, 14-XI- 1945, Ogloblin ( MLP) ; 3♀, San Isidro, Reserva Ribera Norte , 20-I-2009, R. González-Vaquero ( MACN) ; 6♀ 1♂, San Isidro, Refugio Ribera Norte , 28-I-2005, A. Roig Alsina ( MACN) ; 12♀, San Isidro , XI-1982, Genise ( MACN). Corrientes ; 1♀, Santo Tomé (- 28.55S - 56.073W, 72 m. a.s.l), 23-IX-2012, Alvarez ( MLP) . Entre Ríos; 15♀ 28♂, Pueblo Liebig , II-1996, 16-II-1998, L.M. Caire ( MLP) ; 6♀, Chajarí , 24-III-2010, Alvarez-Lucia ( MLP) ; 2♀, Concordia , - II-1991, Hazeldine ( MACN) ; 2♀, Liebig , 19-XII-2004, A. Roig-Alsina ( MACN) ; 1♀, Concordia, Daguerre (28562) (MACN); 2♀, Concordia, Pque. San Carlos, (-31.368915 -57.997303), R. GonzálezV. (MACN); 29♀, R. Uruguay n.e. Concordia , 12-13-I-1980, C. & M. Vardy ( NHMUK). Misiones ; 13♀, Misiones, 4-II-1909, 27-IX-1909, 11-X-1909, 19-III-1910, Jørgensen ( MLP) ; 2♀, Loreto, Ogloblin ( MLP) ; 6♀, Loreto, IV-1933, Ogloblin ( MLP) ; 8♀, San Pedro, Pque. P. Araucaria (- 26.63S - 54.104W, 545 m. a.s.l), 15-XII-2011, Alvarez ( MLP) ; 3♀, El Soberbio (- 27.297S - 54.194W, 143 m. a.s.l), 15-XII-2011, Alvarez ( MLP) ; 2♀, Puerto Iguazú (- 25.604S - 54.586W, 178 m. a.s.l), 27-IX-2012, Alvarez ( MLP) ; 7♀, San Pedro, Pque. P. Cruce Caballero (- 26.52S - 53.987W, 607 m. a.s.l), 19-II-2012, G. Dellapé-D. Barrasso ( MLP) ; 4♀, Pindapoy , 10-29-I-1959, Raimondo ( MLP) ; 11♀, Parque Nacional Iguazú , (- 25.69S - 54.478W, 241 m. a.s.l), 1-12-IX-2013, Ramello ( MLP) ; 4♀, Parque Nacional Iguazú , (- 25.69S - 54.478W, 241 m. a.s.l), 9-IX-2013, Alvarez ( MLP) ; 40♀ 6♂, Parque Nacional Iguazú , Dest. Apepú, (- 25.563S - 54.596W, 217 m. a.s.l), 5-7-IX-2013, Alvarez ( MLP) ; 123♀, Parque Nacional Iguazú , 19- IX-2008, 23-IX-2008, 26-IX-2008, 17-XI-2008, 18-XI-2008, 16-XII-2008, 13-II-2 0 0 8, 14-II-2009, Zamudio- Collesselli-Gómez de Olivera ( MLP) ; 180♀, Parque Nacional Iguazú , 19-IX-2008, 23-IX-2008, 26-IX-2008, 17- XI-2008, 18-XI-2008, 16-XII-2008, 13-II-2008, 14-II-2009, Zamudio-Collesselli-Gómez de Olivera (IBSI-Api) ; 3♀, San Ignacio , 4-5-IV-1974, C. & M. Vardy ( NHMUK) ; 11♀, Puerto Bemberg , Alto Paraná, 13-14-XII-1933, 7- 21-III-1934, K.J. Hayward ( NHMUK) ; 1♀, Parque Nacional Iguazú, Hostería Hoppe c. 140m. Malaise trap, 10-11- IV-1974, C. & M. Vardy ( NHMUK) ; 2♀, Dos de Mayo c. 500m, 7-IV-1974, C. & M. Vardy ( NHMUK) ; 8♀, Misiones ( MACN) ; 9♀, San Pedro, 16-XI-1973, Willink-Tomsic ( IFML) ; 7♀, Misiones ( MACN) ; 3♀, Puerto Aguirre (=Puerto Iguazú), III-1934, K. Hayward ( MACN) ; 3♀, Depto. San Javier, Puerto Londero , IX-1947, Viana ( MACN) ; 2♀, Depto. Apóstoles, 4 Km S Azara, F. Vossler (MACN); 3♀, Urugua-í , IX-2005, F. Vossler ( MACN) ; 3♂, Posadas, Barrio Laurel , 10-XII-1993, A. Tricio ( MACN) ; 55♀, Oberá, Campo Ramón, Nido en chacra de Holl, 18-X-2010 ( MACN) ; 1♀, Oberá, Campo Ramón , 28-IV-14, Alvarez ( MLP) .

Figures

FIGURES 6 – 14. Plebeia emerinoides (Silvestri). 6 – 9, worker; 10 – 14, male. 6 – 8, head of worker in frontal view; 6, specimen from El Soberbio, Misiones; 7, specimen from Pueblo Liebig, Entre Ríos; 8, specimen from San Isidro, Buenos Aires; 9, scutum and scutellum in dorsal view; 10 and 11, head of male in frontal view; 10, specimen from Posadas, Misiones; 11, specimen from San Isidro, Buenos Aires; 12, fifth metasomal sternum; 13, sixth metasomal sternum; 14, genital capsule in dorsal view. Scale bars 6 – 11: 0.5 mm; 12 – 14: 0.25 mm.

FIGURES 15 – 16. Occurrence maps of Plebeia droryana and P. emerinoides in Argentina. Blue circles, P. droryana. Red squares, P. emerinoides. Star, Santa Ana, type locality of P. emerinoides. Triangle, Villarica, type locality of Trigona nigriceps Friese. Cross, Montevideo, Uruguay, southernmost record of Mourella caerulea.