Caenohalictus Cameron

Gonzalez-Vaquero, Rocio Ana & Roig-Alsina, Arturo, 2013, Revision of the species of the bee genus Caenohalictus (Hymenoptera: Halictidae) occurring in Argentinean Patagonia, Zootaxa 3670 (4), pp. 493-515 : 495-496

Caenohalictus Cameron

Caenohalictus Cameron 1903: 231 . Type species: Caenohalictus trichiothalmus Cameron 1903 , monobasic.

Caenohalictus is defined among the genera of Caenohalictina by the following combination of characters: Body metallic dark green or blue, sometimes with a reddish tint, rarely black; compound eyes with conspicuous hairs; mesoscutum reticulate ( Fig. 1 ); dorsal surface of metapostnotum microareolate, finely striate in some species; compound eyes emarginate, inner orbits converging below; female with dark apical band of clypeus extending along the inner orbits, with very inconspicuous punctures, usually reaching the level of the antennal sockets; female with inner hind tibial spur pectinate; male with pygidial plate surrounded by a carina; male genital capsule ventrally concave, gonostylus developed into several processes, directed ventrally.

Gonçalves and Melo (2009) recovered two synapomorphies for the genus: T1 and T2 with lateral carinae present ( Fig. 2 ), also on T 3 in some species, and the male metapostnotum medially depressed. The lateral carinae, probably better described as sulci with slightly elevated margins ( Fig. 2 ), are present on T1 and T 2 in Agapostemon chapadensis , A. nasutus , A. tyleri , Pseudagapostemon citricornis and P. pampeanus , species that were studied by Gonçalves and Melo (2009), although they reported that the lateral carinae are restricted to T 1 in these species. Gonçalves and Melo (2009) mentioned an S8 as long as wide as a synapomorphy of Caenohalictina. All the species examined herein had the S8 much broader than long, in contrast to the species of Caenohalictus they included. In this light, a revision including all the species of the genus and further studies about the genera related to Caenohalictus are needed to set new synapomorphies for this genus.

Rojas and Toro (2000) provided detailed descriptions for the species of Caenohalictus from Chile, as well as descriptions of the main features of the genital capsule of the male. Despite this, the illustrations of the capsules are difficult to interpret, and some steps in the key to the species for the females are hard to follow.

Figures

FIGURES 1 – 2. 1, mesoscutum of C. thamyris, male. 2, lateral sulcus of T 2 of C. opaciceps, male. Scale 1, 200 µm; 2, 20 µm.