A Preliminary Checklist of the Orchid Bees ( Hymenoptera : Apidae : Euglossini ) of Ecuador

A checklist of Euglossini in Ecuador is given, including all currently described, valid species collected until 2018. The list has been assembled frommuseumrecords, fieldwork citedherein, and literature.The former species lists are nearly doubledhere,with 1Aglae, 23 Eufriesea, 68 Euglossa, 18 Eulaema, and 5 Exaerete, 115 in total with >50 new records for the country.Distribution and collection data are included, and some doubtful species are discussed. The Amazon region is the most species rich area but not necessarily a natural pattern, perhaps due to uneven sampling effort across the country. Southern Ecuador is relatively little sampled.

Ecuador is well known as a megadiverse country with an outstanding diversity of organisms and ecosystems and considered important for conservation proposes, e.g., the Tumbes-Choco-Magdalena region and the tropical Andes [38,39].At the same time, from the species records examined here and from biogeographic analyses of other apidologists, e.g., [13,40], it is clear that the NW of Ecuador is quite similar to Central America, while Amazonian Eastern Ecuador and the Andes have some different species.Additionally, among the well-studied Ecuadorian palms, although most species are Andean compared to other regions, 60% of them are from adjacent lowlands; i.e., they are not Andean endemics [41].
Here we update the taxonomic base of knowledge on Ecuadorian euglossines.Only two publications had reported, in general, species for Ecuador.Ramírez et al. [19] report 62 species and Moure et al. [18] report 63.Recent articles treat the taxonomy of the orchid bees of Ecuador, mainly focusing on the description of new species, Euglossa samperi [42]; Euglossa natesi [43]; Euglossa williamsi [44], Euglossa celiae, and Euglossa subandina [45].As part of our continuing study of euglossines in Ecuador and elsewhere, while not listing unnamed species here (as for Meliponini, see [46], or Euglossini, [47]) we attempt to bring euglossine taxonomy up to date, particularly in western South America, and include limited discussion of taxonomic problems.

Discussion
With 115 species reported for Ecuador, our results almost double the number known from previous work [19] (62) and [18] (63 species).In a medium elevation area of north central Peru [81] there may be similar species richness, but as we suggest below, the highest species diversity occurs, as in many groups, in NE Ecuador.
In Ecuador, the genus Euglossa is the most diverse, with 68 species, followed by Eufriesea 23, Eulaema 18, Exaerete 5, and Aglae 1 species.Fifty-two new species records are added for the country, compared to the most recent species list, in [18].The new species records are distributed in four genera.Thirty-nine new species records are added for the genus Euglossa, 4 new species records for Eulaema, 9 new species records for Eufriesea, and 2 new species records for Exaerete (Table 1).There are at least 10 more undescribed species.
Finally, for the monotypic genus Aglae, here we added new distribution records for its conspicuous species A. coerulea Lepeletier & Seville, 1825, in Napo, Pastaza, and Esmeraldas Provinces, extending its known distribution to the Eastern Andes in Ecuador.Previously it was reported for Ecuador by [50] from the Chocó Region in western Ecuador.
Our results show a clear richness pattern (Figure 1), with a concentration of species in the Amazon region.As noted by previous authors [13,19,40,66] the northwest is similar to Mesoamerica and Panama.The Andean and inter-Andean region, between the Cordillera Occidental and Oriental, may hold endemic euglossines, but the overall similarity to Peru and Colombia does not permit such a view at present.The lower to medium elevation Andes region may, like the palms [41], hold the most species.For now, most Ecuadorian euglossines have been found east of the Andes, in the lowlands.This is perhaps the result of more intensive sampling there, especially at the Estación Biológica Yasuní.It is also clear that some areas are poorly sampled, especially the southern part of Ecuador.In those areas, such as the Cordillera del Condor, Cerro Plateado, Zapotillo, and Zumba Regions, more new species records for the country will likely be found, as is now the case in Yasuní forest, in the northeast.
Any single reported collection should, for the time being, be viewed with some skepticism and needing replication and confirmation.The single recorded specimens that differ from the gender of the designated holotype, for example, the male of Eufriesea combinata or Eufriesea theresiae [51], require further field work to validate.We see a need to emphasize that some species are quite difficult to identify and distinguish, likely due to mimicry, and phylogenetically close relatives that first separated by climate changes during glaciations, either on both sides of the Andes or in higher elevation areas, compared to lowlands.There are reasonably cryptic sibling or close relatives.For example, Euglossa chalybeata and E. piliventris, previously thought to be native to Ecuador, have yet to be found there, but in their place Euglossa orellana, E. occidentalis, and E. lugubris were described [65].Similarly, Kimsey [13] pointed out the synonymy of Eufriesea andina with its senior synonym, Ef. magrettii, and the color polymorphism of the males in both this species and Ef.venezolana, which had confused previous taxonomic work.We find also very slight differentiation between two Eulaema and subgenus Apeulaema, although some of the reported males in Ecuador may in fact match those of French Guiana-the type area for Eulaema cingulata-and we have examined two from Eastern Ecuador that are different, one indistinguishable externally from Eulaema of Panama, which is now tentatively given the name Eulaema marcii, but which was described from Eastern Brazil.Further study of genitalic details would repay the effort.

Table 1 :
New species records added for Ecuador.
2.1.Material Examined.All material examined from museums came from the following institutions: INABIO: Instituto Nacional de Biodiversidad, Quito-Ecuador.Psyche