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Protodufourea, Sphecodosoma and Xeralictus identification guides

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  • Michael Orr
    Hello, Three more Western US groups have been completed. They are the Protodufourea, Sphecodosoma and Xeralictus, all of which are members of the subfamily
    Message 1 of 1 , Sep 6, 2011
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      Hello,


      Three more Western US groups have been completed. They are the Protodufourea, Sphecodosoma and Xeralictus, all of which are members of the subfamily Rophitinae (Halictidae). All three groups have relatively few species (5, 3 and 2 respectively).

      Although sufficient specimens were available for the Sphecodosoma and Xeralictus, Protodufourea wasbaueri was in short supply so it would be extremely helpful for anyone with access to this species to run it through the key quite critically. As always, any suggestions or concerns may be directed to me (michael.christopher.orr@...). 


      Protodufourea characters:
      Female, abdomen, T2 and T3, hair density in middle of segment - Be careful, as hair loss here can become misleading
      Absent or nearly so, clearly less dense medially than at the sides (eickworti, koso)
      As dense as is seen at the sides (parca, wasbaueri, zavortinki)

      Female, abdomen, integumental color
      Entirely black, without red (eickworti, koso, parca, wasbaueri, zavortinki)
      Noticeably reddened at least in part, but sometimes almost entirely so (eickworti, koso)

      Female, rear leg, scopa, hair color
      Primarily light, if with any darker hairs then they are almost always limited to the top of the tibia near the basitibial plate (eickworti, koso, parca, zavortinki)
      With significant amounts of both light and dark hairs, usually with the dark hairs near the basitibial plate reaching around the outer face of the tibia (eickworti, wasbaueri)

      Female, P. eickworti vs P. koso
      P. eickworti - The area of the propodeal triangle bordering the metanotum is strongly rugose, with lines running roughly longitudinal in the basal half - Pitting of T1 sparse medially, the average interpit distance variable but usually around three pit diameters or greater
      P. koso - The basal half of the propodeal triangle bordering the metanotum is tessellate, with only weak patterning that makes the surface appear similar to sandpaper - Pitting of T1 closer, the average interpit distance usually equal to 1-2 pit diameters

      Female, P. parca vs P. zavortinki
      P. parca - The clypeus is relativfely evenly pitted throughout, if less dense apically then it is only a slight difference and there are still pits present in the area - The pitting of T1-3 is denser basally than apically, ranging from below one pit diameter to sometimes over one pit diameter, with the pits in the denser area usually slightly smaller than those that are more well-separated - The first recurrent vein meets the bottom of the second submarginal cell slightly before the end of the cell, usually by about 1-2 vein lengths
      P. zavortinki - The apical third to half of the clypeus is almost entirely unpitted and shiny, at least medially - The pitting of T1-3 is about equally dense throughout, about one pit diameter, and although the pit size may vary throughout there does not seem to be a trend of smaller pits basally - The first recurrent vein meets the second transcubital vein linearly, right at the end of the second submarginal cell

      Male, S6, shape of the medial emargination - Caution, this is subtle and tricky without comparative material, be very careful with your diagnosis here
      Roundedly concave throughout (parca, wasbaueri, zavortinki)
      Roundedly concave for the most part, BUT the middle of the concave area is somewhat flattened with a slightly medial bump which is often hard to see (koso)
      With a V-shaped concavity, which comes to a point medially (eickworti)

      Male, abdomen, S2-4, color of the medial patches of short, dense hair
      Lighter, whitish to very slightly off-white (eickworti, parca, zavortinki)
      Darker, brownish, sometimes a golden brown color and sometimes much darker (koso, wasbaueri)

      Male, abdomen, S2-4, form of the medial patches of short, dense hair
      Thick, often somewhat blob-like, such that they are less than twice as latitudinally broad as they are longitudinally wide (eickworti, parca, wasbaueri)
      Thin, appearing linear, such that they are 2-3 times more latitudinally broad then they are longitudinally wide (eickworti, koso, wasbaueri, zavortinki)


      Sphecodosoma characters:
      S. beameri vs S. dicksoni and S. pratti
      S. beameri - The pit interspaces on the head between the ocelli and antennal fossae are small, usually under one pit diameter - The pitting of the scutum is very distinct due to its coarseness, these pits much larger than those of the other two species and are readily visible under a microscope - The pit interspaces on the scutum average one or less in females and 1.5-2 in males
      S. dicksoni and S. pratti - The pit interspaces on the head, between the ocelli and the antennal fossae, are large, usually equal to several pit diameters and often quite variable - The pitting of the scutum is often hard to see except at certain angles, this due to the relatively small size of the pits - The pit interspaces on the scutum usually average over two pit diameters

      S. dicksoni vs S. pratti - Small, but consistent, differences
      S. dicksoni - The propodeal triangle is roughened at its base but becomes smooth and shiny along its posterior rim where it bends over to the lateral face as well as at the sides of the triangle, best seen when looking down at the propodeum
      S. pratti - The dorsal face of the propodeal triangle is roughened and dulled to its posterior rim medially, but at the sides this area is smooth and shiny, best seen when looking down at the propodeum


      Xeralictus characters:
      Female, X. bicuspidariae vs X. timberlakei - Best differentiated by direct comparison with specimens
      X. bicuspidariae - The head is usually slightly longer than broad - The integument of the abdomen is at least partially, but almost always primarily, reddened - In direct comparison, this species is smaller than X. timberlakei, usually around 10mm in length
      X. timberlakei - The head is usually slightly broader than long - The integument of the abdomen is primarily blackish, although in some areas it may appear to be a DARK reddish-brown - In direct comparison, this species is larger than X. bicuspidariae, usually around 13mm

      Male, X. bicuspidariae vs X. timberlakei
      X. bicuspidariae - On S4, the broad tip of the rear-directed, central projection that arises from the rim appears relatively flat or slightly convex, with the sides of the projection remaining roughly parallel as they travel to the rim of S4 - On S5, the lateral tips of the similarly rear-directed, central projection are more broadly rounded, lobe-like and without a defined point at the tip - In direct comparison, this species is smaller than X. timberlakei, usually around 10mm in length or slightly larger
      X. timberlakei - On S4, just before the tip of the central projection the sides angle inward such that each side has a slight lateral indent on either side of the tip of the projection such that the rim appears interrupted at the sides, with the sides of this projection clearly wider near the tip than at the base of the projection - On S5, the lateral tips of the central projection are pointed, appearing as acute angles usually around fifty degrees - In direct comparison, this species is larger than X. bicuspidariae, approaching 15mm in length


      -Michael Orr
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