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Ancylandrena and Dioxys identification guides

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  • Michael Orr
    Hello, Two more new guides have been completed for the US. They are the Ancylandrena and Dioxys, with five species in each. These are western genera once
    Message 1 of 1 , Sep 11, 2011
      Hello,


      Two more new guides have been completed for the US. They are the Ancylandrena and Dioxys, with five species in each. These are western genera once again. As always, any suggestions or issues should be sent to me (michael.christopher.orr@...).


      The Ancylandrena guide was completed in part thanks to Zavortink's 1974 publication on the genus and the specimens used were provided by the Logan lab bee collection. The guide may be found at the URL below:
      http://www.discoverlife.org/mp/20q?guide=Ancylandrena

      Ancylandrena characters:
      Mandible, presence of a tan or light-colored, often translucent or transparent, mound at the base of the mandible
      Absent - There may or may not be a slight bump, but it IS NOT significantly lighter than the rest of the mandible (atoposoma, timberlakei)
      Present (larreae, koebelei, rozeni)

      Female, hind tibial scopa, hair color
      Entirely light save for a small patch right behind the basitibial plate, this patch appearing a LIGHTER color than the integument of the basitibial plate itself (atoposoma, koebelei)
      Mostly light, but with a patch of dark hair directly behind the basitibial plate which is as dark as the integument of the basitibial plate (atoposoma, larreae)
      With both light and dark hairs, the hairs lining the edge of the tibia from the basitibial plate to the apex of the tibia appearing darker than those lower on the outer face of the hind tibia (timberlakei)

      Female, abdomen, sternal scopa - The scopa is usually longest in the apical half of each individual sternite and is often densest medially
      Present on S1-4, the hairs of which are about equal in length on these segments (koebelei, larreae)
      Present and about equal in length on S1-2, but the hairs are medially shorter on S3 and much shorter on S4 (atoposoma, koebelei, timberlakei)

      Female, A. koebelei vs other species
      A. koebelei - At the base of the mandible there is a nearly transparent whitish to off-white and somewhat bulbous mound, which usually takes up about a fourth of the total length of the mandible, and often the light coloration extends past the mound up to half the length of the mandible - The apical hair bands of T2-3 are widely interrupted such that the medial third to fourth of the rim lacks a hair band - The dense area of hairs at the middle of the rim of T5 is orangish 
      Other species - If there is ANY mound present at the base of the mandible, it is most often brownish and small enough that it takes up less than a fourth of the length of the mandible - The apical hair bands of T2-3 are only narrowly interrupted if at all, the rim almost entirely covered - The dense area of hairs at the middle of the rim of T5 is dark brown or black

      Male, A. atoposoma vs A. timberlakei
      A. atoposoma - The apical rim of the labrum is flat, running about straight across from one end to the other - The yellow marking in the paraocular area is usually widest at the middle and tapers at each end, if widest in the bottom half then it is only very slightly wider here in comparison to the average width of the top half - There are significant numbers of brownish or blackish hairs present posterior to the ocelli
      A. timberlakei - The apical rim of the labrum is somewhat convex, smoothly and slightly rounded outward - The yellow marking in the paraocular area is usually widest in the bottom half such that it appears vaguely triangular, often broad enough at its base to almost reach the clypeus - The hairs posterior to the ocelli are all white or very nearly so

      Male, A. koebelei vs other species
      A. koebelei - At the base of the mandible there is a nearly transparent whitish to off-white and somewhat bulbous mound, which usually takes up about a fourth of the total length of the mandible, and often the light coloration extends past the mound up to half the length of the mandible - The clypeus is largely whitish to yellowish along the rim, this color tapering back up towards the antennal fossae - The hair on the front edge of the fore femur is many times longer than the very short hairs found elsewhere on its surface
      Other species - If there is ANY mound present at the base of the mandible, it is most often brownish and small enough that it takes up less than a fourth of the length of the mandible - The clypeus is dark brownish or black throughout - The hair length on the fore femur is about evenly long throughout, where present, and is often LONGEST on the rear face of the femur
       
      A. rozeni vs other species - The creator of this guide has not yet seen specimens of this species and used the description by Zavortink as a result
      A. rozeni - This is a rare species with records restricted to Arizona, specifically known from the Tuscon area - The male appears closest to that of A. larreae though slightly smaller, has a shorter clypeus, has shorter antennae, has smaller light markings in the paraocular area, is less densely pitted anteriorly on the scutum, hairs sparser in the anterior of the scutum, and has a greater proportion of dark hair on the upper areas of the head - The female appears most similar to that of A. timberlakei, although it may be differentiated by the presence of some degree of a tan or yellowish brown mound on the base of the mandible, a greater proportion of dark hairs in the upper areas of the head, the fact that all hairs anterior to the middle of the tegulae are white, and that there is a greater proportion of light-colored hairs on the scopa
      Other species - Not as above


      The Dioxys guide was completed in part thanks to Hurd Jr's 1958 publication on the genus and the specimens used were provided by the Logan lab bee collection. The guide may be found at the URL below:
      http://www.discoverlife.org/mp/20q?guide=Dioxys

      Dioxys characters:
      Female, abdomen, S6, shape of rim
      Coming to a vaguely triangular point which is rounded at the tip, sides roughly straight toward the tip or only slightly convex (pacifica)
      Rounded outward throughout such that it appears as a semicircle, not concave on the sides, resembling a thumb tip (aurifusca, producta)
      The tip is convex but the sides are slightly concave just before the tip, which makes the tip appear more produced (pacifica, pomonae)

      Female, abdomen, length of S6 vs T6
      With S6 shorter than T6 (aurifusca, producta)
      With S6 and T6 of about equal length (producta)
      With S6 longer than T6 (pacifica, pomonae)

      Male, T6, form of the apical rim
      1. Strongly produced such that it nearly comes to a point, the tip with a small emargination or shallow concave area in the center of the rim (aurifusca)
      2. Convex, rounded throughout (pacifica, producta)
      3. Straight but usually very slightly concave in the center, but usually only very slightly and thus the rim normally appears somewhat flat as a result (pomonae)

      Male, D. pacifica vs D. producta
      D. pacifica - The pronotal lobe is weakly carinate, often hard to tell if it completely divides the pronotal lobe from the rest of the pronotum due to the low height of the carina, which may be measured as about one adjacent pit diameter or less in height
      D. producta - The pronotal lobe is strongly carinate, completely and obviously dividing the pronotal lobe from the rest of the pronotum thanks to the height of the carina, which may be measured as several pit diameters in height

      D. aurifusca vs other species
      D. aurifusca - Distinct golden hairs present throughout the body, these often most obvious on the terga where the inidvidual hairs are often HEAVILY BRANCHED at the base and thus somewhat triangular in shape as a result
      Other species - The hairs of the body are white to off-white in color, usually not triangular in shape

      D. rohweri vs other species - The guide creator has not seen this species and is referencing the key by Hurd Jr
      D. rohweri - There is no description given for the female, but it is assumed rare due to its restriction to Colorado - The male is similar to that of pacificus, although it may be differentiated from that species by a small, semicircular emargination medial in the rim of S2
      Other species - Not as above


      -Michael Orr
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