Xylocopa dimidiata Latreille, 1809

Lucia, Mariano & Gonzalez, Victor H., 2017, New species and designation of primary types in Neotropical carpenter bees of the genus Xylocopa Latreille (Hymenoptera, Apidae), Journal of Hymenoptera Research 61, pp. 31-48 : 43-45

Xylocopa dimidiata Latreille, 1809 Figs 17-21

Xylocopa dimidiata Latreille, 1809: 95, pl. 38. (Neotype: BMNH; ♀, Brazil, Ega [ Tefé]) (new neotype designation).

Xylocopa batesi Cockerell, 1907: 228, new name for " Xylocopa dimidiata Smith", nomen invalidum (not X. dimidiata Latreille, 1809 and X. dimidiata Lepeletier de Saint-Fargeau, 1841 [= X. ocularis Pérez, 1901]).

Diagnosis.

This species can be recognized by the combination of the following features: medium body size (body length 23 mm); integument black, with distinct metallic green highlights on metasoma and mesosoma, particularly on mesoscutellum, and head with blue metallic highlights (Figs 17 , 18 , 20 ); wings dark brown with violet highlights except apex green (Fig. 19 ); pubescence black; labrum basally with a distinct, large, single capitate tubercle, about as large as OD; T1 with plumose and simple setae; discs of T2 and T3 with very short, simple setae, each seta barely exiting puncture (Fig. 20 ); and T4-T6 with long setae, 1-2 times longer than those on T2 and T3.

Comments.

The identity of Xylocopa dimidiata proposed by Latreille (1809) has been a mystery and its current concept encompasses more than one species (Fig. 22 ). Latreille proposed Xylocopa dimidiata from a single female collected somewhere along Alexander von Humboldt and Aimé Bonpland’s voyage and whose whereabouts are unknown ( Hurd 1978, Moure 2007). More than 60 years after Latreille’s description, Smith (1874) identified and briefly described a female specimen from Ega [ Tefé], Brazil, as what he interpreted to represent X. dimidiata Latreille. Subsequent authors followed Smith’s concept of X. dimidiata and even incorrectly attributed the name to him, despite Smith making a clear reference to Latreille when using the name (e.g., Schrottky 1902). In fact, because Cockerell (1907) thought that Smith had proposed X. dimidiata in 1874, which then would result in homonym with Latreille’s X. dimidiata as well as with one established by Lepeletier (1841), he proposed to replace Smith’s name with X. batesi Cockerell ( Hurd 1959). However, because Smith (1874) did not establish a name, Cockerell’s replacement name for an unavailable name is therefore invalid under the ICZN (nomen invalidum). For the same reasons, the synonym of X. batesi under X. dimidiata Latreille listed by Hurd and Moure (1963), Hurd (1978), and Moure (2007) are unavailable.

The specimen identified as X. dimidiata by Smith is in the NHML (Figs 23-26 ), along with the specimen from the same locality herein designated as the neotype of that species. The second specimen is in better condition than that identified by Smith and, judging by the handwriting of the labels, it appears to be from the same collection event. Given the confusing identity of X. dimidiata , the designation of a neotype is necessary to stabilize the name. For practical reasons, we chose as the neotype a specimen that matches Smith’s concept of X. dimidiata Latreille. Although this proposed taxonomic action resolves the identity issue of X. dimidiata , there is no reason to assume that Smith’s interpretation of Latreille’s X. dimidiata is correct. First, Smith’s specimen is from the Amazon Basin, in a locality well outside of the route taken by Humboldt and Bonpland. These explorers traveled through large areas of Venezuela and the Magdalena River Valley in Colombia and through the Andes southward to Lima, Peru, and Guayaquil, Ecuador, before traveling to Mexico (e.g., Sandwith 1925, 1926, Papavero 1971). Thus, Latreille’s specimen could have been collected from any of these areas bordering the Amazon Basin, unless it came from San Carlos de Río Negro in Venezuela’s Amazonas state. Second, specimens standing in collections under X. dimidiata actually belong to multiple species, distinct from Smith’s material. This is the case for the Bolivian specimens described herein as new ( X. barbarae ), which superficially fall within the historical concept of Smith’s X. dimidiata , but differing in the longer and denser pubescence of terga, presence of white setae on sides of T2-T4, and wings with violet highlights throughout. Thus, Smith’s concept of Latreille’s X. dimidiata is questionable, and the current application of this name includes several species.

Given the problems outlined above, we initially thought that it would be best to regard X. dimidiata Latreille as a nomen dubium, meaning that future workers would have the task to fix this name to one of those biological species overlapping Humboldt and Bonpland’s route. Xylocopa (Schonnherria) is the second most species-rich group of Xylocopa in the Western Hemisphere, containing about 30 species ranging from southern United States to southern Argentina ( Michener 2007). Because taxonomic issues like these are best resolved in a context of a revision, a study of such a magnitude might take several years to complete, if done at all. Thus, despite all problems surrounding the identity of X. dimidiata , we chose to designate a neotype for this species following Smith’s interpretation. This might not be Latreille’s concept of X. dimidiata but we believe this taxonomic action now would be beneficial to the advancement of the taxonomy of the group. The label data for the specimen here designated as the neotype are as follows: 5669 / Ega / 5669 / Ega / Neotype, Xylocopa dimidiata Latreille des. M. Lucia V.H. Gonzalez ♀.

Figures

Figure 22. Schematic representation of the historical changes in the species concept and nomenclature surrounding X. dimidiata Latreille (see text for details). The yellow and blue columns each represent a species concept.

Figures 17 - 21. Neotype of X. dimidiata Latreille. 17 Facial view 18 Dorsal view of head and mesosoma 19 Left fore and hind wings 20 Detail of metasomal terga 21 Associated labels (NHML).

Figures 23 - 26. Specimen of the NHML identified as X. dimidiata Latreille by F. Smith. 23 Facial view 24 Dorsal view of head 25 Detail of terga 26 Associated locality and determination labels (Photographs by David Notton, NHML).