Eurygaster shoshone

Eurygaster shoshone is an odd ball within the Nearctic Eurygaster spp. and the only one of the bunch that would be classified in the subgenus Eurygaster sensu stricto (with the European Eurygaster hottentotta as type species) if historically defined subgenera would merrit world wide usage.
E. shoshone is recognizable by the postero-lateral margin of pronotum (margin behind the bluntly rounded shoulder) being very clearly _very_ sinuate and the scutellum clearly keeled medially.
Please be aware that other species will often have a clear medial stripe on the scutellum that also carries less punctures, making it look like a keel optically, but not actually keeled(!)

comments (11)

Pudding4brains

Lion

Some Eurygaster sp. - you'll need this to identify it (I don't have it):
Vojdani S. (1961) The Nearctic species of the genus Eurygaster. - The Pan-Pacific Entomologist, vol.37, pp.97–107 Posted 8 years ago
1. morpheme
  
  Lion
  
  that's super helpful - BugGuide says we've only got possibly 5 species in North America and only has two with any photographs to show (which appears to indicate that they are uncommon), so I may be able to ID - thanks! Posted 8 years ago, modified 8 years ago
2. 1. Pudding4brains
    
    Lion
    
    Bugguide only has images of 2 of the 5 species and I wasn't convinced by those (white border on pronotum, pronotum shaped slightly different, clypeus/jugae not convincingly similar ...) Most Eurygaster species in Europe are very variable in colour and sometimes even somewhat in morphological shapes and I have zero knowledge of the Nearctic species.
    Will see if I get around to asking David Rider if he has better ideas or maybe the key ... Posted 8 years ago
  2. 1. morpheme
      
      Lion
      
      yeah - one of the comments on BugGuide was that their color is quite variable and gives little clue to species. The name Dave Rider actually comes up too - he gave someone a scanned copy of the article you mentioned. One of the small tidbits I did find was about habitat, that E. amerinda is found in drier areas than E. alternata. My guess is based mostly on that - the area that it was in is quite dry (sage brush) and that a good number of the E. amerinda examples on BugGuide came from up here in Washington. Then again I have no idea about the several other species that it could be. Unfortunately right after I took that photo it surprised me and flew away... so I've not got any other or better views... Posted 8 years ago, modified 8 years ago
    2. 1. Pudding4brains
        
        Lion
        
        David Rider is one of the foremost researchers of Pentatomidae, not only for the US but world wide I would think. For example he is the author of the volume on Pentatomidae in the catalogue of the Palearctic Heteroptera (eds. Aukema & Rieger) and a very friendly, helpful person to boot :o)
        Here is his website: https://www.ndsu.edu/faculty/rider/Pentatomoidea/Researchers/Rider_David.htm Posted 8 years ago
      2. Pudding4brains
        
        Lion
        
        David kindly sent me a few documents and also passed my request on to Joe Eger who apparently is more into the Scutelleridae. He responded with an unpublished dissertation by John Daniel Lattin (1964) that was quite helpful in two respects:
        a) It stresses that Eurygaster is a regular PITA to identify on external characters and that much misidentification, confusion and pointless description of "new species" has resulted from this (also diagnosed as such by Vojdani in the article mentioned above) and that as such male genitalia should be examined (and proper preparation of those is also problematic)
        b) Nevertheless he also provides a key based on external characters (as well as a key on male genitalia) and in this key your specimen would unambiguously key out to Eurygaster shoshone, based on two characters clearly recognizable in your photo that the other species should not have:
        1) Postero-lateral margin of pronotum very clearly _very_ sinuate
        2) Scutellum keeled medially
        Everything else I read collaterally seems to just corroborate that analysis, so I'm fairly confident we may identify your image under that name, but I have asked the experts (just now) if they would agree with that or if point (a) above should weigh in more heavily ...
        
        P.S. Looking at the images of Eurygaster on BugGuide my guestimate would be that the IDs on those are messy/iffy at best. Posted 8 years ago, modified 8 years ago
        
        morpheme
        
        Lion
        
        That's really cool. The attention to these guys on BugGuide certainly isn't great - only two of the species even have photos at all assigned to them and only a few at that. I don't know if that's because they are uncommon or just unloved/unreviled :p. I'd guess our local species must not be too much of an agricultural pest here or they'd get more notoriety. I didn't even bother sending them over the image I had.. I figured they'd reject it as a poor view for ID... Posted 8 years ago
        
        Pudding4brains
        
        Lion
        
        Hi Morpheme,
        As it turns out, your image is excellent for ID and just about the only Nearctic species of Eurygaster that can confidently be IDed from such a photo. I would certainly suggest that you present a closer crop of your image on BugGuide under the correct name as the site is used by many as an ID help. Some of their other images may actually be the same species, but misidentified as some other(!)
        Please keep in mind that all other Nearctic species or Eurygaster are much harder/iffier to ID, so this may well be a reason for limited popularity too.
        
        In various publications it has been suggested that these critters are quite capable of adapting to other food sources such as commercially grown grains when their original habitats are being threatened, and that as such an outbreak of these as important pests is not entirely hypothetical.
        
        Meantime my email discussion with David Rider and Joe Eger has confirmed that the characters visible in your image are indeed sound external characters for recognizing this species, so I will "create" the species on JD shortly (later tonight) and ID your image :o)
        
        I had sent you a personal message about getting your mail address so I might share what info I have received with you - did you not get it? Posted 8 years ago
        
        morpheme
        
        Lion
        
        I used the reply function directly from the message - maybe it didn't work. I'll send again using the email you provided. Posted 8 years ago

Mike van Harn

Musk Oxen

This is what you call a phenomenal recording. Top done. Posted 8 years ago
1. morpheme
  
  Lion
  
  Pudding gets all the credit - I never ever would have ID'd this critter on my own :) - I was still getting nowhere poking through stink bugs (no wonder none of them looked right). The email discussion between the experts was fascinating - so much duplication left over from the days when communications weren't so instant. It makes me wonder as gene sequencing becomes so much cheaper and faster just how much shake up there will end up being in species definitions - especially in plants and insects, which can so often either look the same and be totally different or have a wide range of appearances, but still be the same... Posted 8 years ago, modified 8 years ago

The Eurygaster shoshone

Eurygaster shoshone is a Nearctic species of Scutelleridae ("Shield-backed Bugs"). It is one of around five species in the genus Eurygaster currently known from North America.

Info 1 0

Similar species: True Bugs

Species identified by Pudding4brains