Wednesday, June 26, 2013

A new spiny crawler, Serratella carolina: a trip to the Doyles

My first stop today was Buck Mt. Creek where I was looking for small minnow mayflies.  I didn't find very much: a Gyrinidae (whirligig beetle), a Darner dragonfly, and various and sundry flatheaded mayflies including a nice Leucrocuta which I'll show you all in a moment.  But not doing real well at BMC, I decided to move on to the Doyles, where I fared much better.

Serratella is the genus of spiny crawler that we usually see in the summer, and I was happy to find two nymphs at the Doyles.  The species I normally see is S. serratoides, and I assumed I had found it again.  Still, I thought I should check everything out to be sure -- and it's a good thing that I did.

This morning's nymphs appear to be S. carolina, a species I have not seen before.   Here is Beaty's species description ("The Ephemeroptera of North Carolina," p. 31).

S. carolina -- nymphs 4.5-5 mm; maxillary palpi one apparent segment; tarsal claws with 5-7 denticles; occiput, pronotum and abdominal terga 3-9 with paired submedian tubercles.  Adults not known.  Found in Mountains only.  Relatively common.

One of my nymphs was 4.5 mm, the other was 5.  On the maxillary palpi, they do appear to have only one segment, but I do not yet have a photo to show that, and I can't tell how many denticles there are on the claws: just can't see that kind of detail with my microscope.

But, the tubercles on the occiput (back of the head) and the pronotum are clear.

So too are the paired submedian tubercles on the abdominal terga, though I will admit they are not easy to see on terga 3 and 9 in this photo.

Let me make two other arguments on this ID.  1) Of the four species of Serratella that Beaty describes, only S. carolina has tubercles on both the pronotum and head.  And 2) the other "common" species of Serratella, the one that I normally see -- S. serratoides -- is very distinct in terms of the sternites: there is "a transverse row of four black dots on each sternite." (Beaty, p. 31)  These.

Now look at the sternites on the nymphs from this morning.

Totally different.  So, I think we have a new species: Serratella carolina.  However, I will continue to examine this further.


One other mystery bug at the Doyles -- a common netspinner, genus Ceratopsyche.

I found two of these larvae and picked them up because of the color -- cream colored bodies with brown nota and heads.  I also found a Ceratopsyche bronta and a Ceratopsyche morosa.  Those I could identify -- this one, so far, I cannot.  What is critical in making this kind of ID is the pattern we find on the head, and I've not seen this one before.

Three, dark horizontal lines in the posterior angle of the frontoclypeus.  I've asked Steven Beaty for help and will get back to you when he responds.

Other photos:

1. Oh yes, I did find some small minnow mayflies at the Doyles: Baetis intercalaris, every nymph that I saw.

2. And as promised, here's the Leucrocuta flatheaded mayfly I found at Buck Mt. Creek.  A beauty!

1 comment:

  1. Hi Bob. Your unknown Ceratopsyche is C. sparna. The head pattern is similar to those found here in Ontario.