My nice tidy world view of eastern Ceratina was soundly disturbed by Rehan and Sheffield's recent revision. Here they added a new species (C. mikmaqi) and resurrected C. floridana. I have procrastinated updating the guides until I got some molecularized specimens from Cory. And then I procrastinated some more.
Finally, I have spent a big chunk of time going over and over specimens to see if I can clarify the differences for DL. Those characters will be online tomorrow. But because this group is common and we all suffer through identifying them I thought I would bring these changes to light.
OK, here are the new characters. Feedback is welcome. Note that C. mikmaqi MAY be quite common in some areas....this is your job to start figuring this out. Also C. floridana should be on everyone's list to look out for in any sandy area from Florida to the Mid-Atlantic and perhaps in the Sandy areas of the Great Lakes. Note, however, that past literature rests heavily in describing the midnight blue southern florida specimens, but largely neglects the fact that this species appears to change color to that of more regular Ceratina to the north.
Have fun ....
Female, C. strenua vs. C. floridana
C. strenua - Abdomen, T4, pitting pattern and the completely smooth surface on basal two-thirds of the segment is similar to that found throughout T3, pitting and surface sculpturing on the apical one-third of T4 is more similar to T5 which is to say that pitting is more hidden partially by surface bumpiness, rugosity, and topography - Abdomen, T3, pit density is dense but comparatively less dense than C. floridana with many instances of clear spaces between the pits on the central latitudinal portions of T3, usually, however, there are a FEW instances where there are spaces that are greater than 1 pit diameter - In direct comparison, SMALLER
C. floridana - Abdomen, T4, surface characteristics found THROUGHOUT this segment are similar to the obscured pitting and greater surface bumpiness, rugosity, and topography found on T5, in direct contrast to the smooth, flat surfaced, and dense pitting found on T3 - Abdomen, T3, pit density is extremely dense with most pits overlapping other pits and while there are some instances of spaces appearing between the pits on the central latitudinal portions of T3, there are NEVER any instances where these spaces are greater than 1 pit diameter - In direct comparison, LARGER - Note, this species range extends to southern Florida where most specimens will be midnight blue in coloration with no green reflections, however, as you move up the peninsula you will find the color shifts to a more typical green-blue coloration of the other Ceratina - This species should be particularly looked for in sandy areas
Male, C. dupla and C. floridana vs C. mikmaqi - Note, the differences between these 2 groups of species is clear and easy to detect once you have both groups available for comparison - Normally C. dupla is the more common species, but C. mikmaqi can occur in substantial numbers at least at some sites and MAY be more associated with dry, sandy locations - C. floridana is the only Ceratina in southern Florida, but it is unclear if the males are differentiable where they mix with C. dupla to the north, C. floridana loses its midnight blue coloration in the north too, unfortunately
C. dupla and C. floridana - Hind Leg, femur, EXTERIOR face, widest point, very slightly below the apex of the VENTRAL angle that forms the outline of the femur when the leg is positioned straight back, at this location there is a very SMALL tuft of pale hairs, perhaps 5-20 in number, but distinct, this tuft of hairs is NOT visible from the interior face of the femur - Hind Leg, femur, VENTRAL edge when viewed with leg extended straight back, the long edge running from the widest point of the femur to the apical end of the femur, this edge is crisply and uniformly sharp, like a knife, along its entire length - Thorax, METEPISTERNUM, pitting on the upper half is dense and the pits are ALMOST ALL OVERLAPPING, thus causing this segment to appear duller and less reflective in comparison to C. mikmaqi, the reflective quality of this segment is more similar to the adjacent lateral face of the propodeum than it is to adjacent and more reflective face of the mesepisternum, expect some variation in pit density and use this as a secondary characteristic
C. mikmaqi - Hind Leg, femur, EXTERIOR face, widest point, very slightly below the VENTRAL angle forming the outline of the femur when the leg is positioned straight back, at this location there are only a few SCATTERED MINUTE pale hairs, these hair are relatively uniformly spaced and would never be thought of as clumped into a tuft - Hind Leg, femur, VENTRAL edge when viewed with leg extended straight back, the long edge running from the widest point of the femur to the apical end of the femur, this edge, while still thin and acutely angled is, in direct comparison, more rounded, minutely so near the widest portion of the femur and the edge increasing in overall thickness and losing definition as it approaches the apical end of the femur - Thorax, METEPISTERNUM, pitting on the upper half is dense but the pits are ALMOST ALL TOUCHING BUT NOT OVERLAPPING, thus causing this segment to appear brighter and more reflective in comparison to C. dupla, the reflective quality of this segment is more similar to the adjacent and more reflective face of the mesepisternum than to the adjacent and duller lateral face of the propodeum, expect some variation in pit density and use this as a secondary characteristic
Female, C. calcarata and C. mikmaqi vs C. dupla - Note that these three species are very closely related and can be exceptionally difficult to distinguish - Expect some to not resolve - Female C. mikmaqi and C. dupla are separated in a separate character
C. calcarata and C. mikmaqi - Thorax, scutum, there is ONE column of pits running down either side of the line that runs down the center of the scutum. This column varies from complete to incomplete, sometimes having gaps where pits are not present. There are rarely additional columns of incomplete pits. Also, running along the INSIDE of the parapsidal line, which is a groove in the scutum running near the tegula, there is ONE column of pits that is almost always INCOMPLETE, usually with NO additional incomplete rows, note that pits cover the entire anterior portion of the scutum in both species
C. dupla - Thorax, scutum, there is one COMPLETE, uniform, regularly spaced column of pits both sides of the line that runs down the center of the scutum and are generally paralleled by 2-3 ADDITIONAL complete or incomplete rows of pits. Additionally, running along the INSIDE of the parapsidal line there is ONE COMPLETE column of pits that is generally paralleled by 1-2 ADDITIONAL incomplete or complete columns of pits. All together a more heavily pitted scutum is present
Female, C. calcarata vs C. mikmaki - This should be treated as an experimental couplet. Likely this is the right path to identify this pair, but likely not infallible
C. calcarata - Head, clypeus, yellow to white central mark, at times this mark is completely absent, sometimes small, but appears to regularly be as long as that of C. mikmaki, reaching all the way to the border with the supraclypeus - Abdomen, sternites, the sparse, slightly slanting rearward, tall, prominent hairs are BRIGHT WHITE and, while sparse, are clearly less so in comparison to C. mikmaqi, this character is best viewed by holding the specimen upside down and viewing the sternites from the side
C. mikmaki - Head, clypeus, yellow to white central mark, at this point all known or suspected specimens have a large and prominent mark that runs from the just shy of the rim of the clypeus to at least two-thirds of the way to the border with the supraclypeus - Abdomen, sternites, the sparse, slightly slanting rearward, tall, prominent hairs are tinged slightly OFF-WHITE to TAN and, vary from absent to a handful, often fewer than 10