Author Topic: Posterior abdominal segments curving to ventral  (Read 4327 times)

Martin Spies

  • Administrator
  • *****
  • Posts: 112
Posterior abdominal segments curving to ventral
« on: May 29, 2014, 07:43:33 AM »
In e-mail to the late Ole Sæther in November 2011 I asked the following question:
"About Paraphaenocladius larval morphology: It seems to me that the abdominal segment that is bent to ventral, so that the procerci end up in a 'terminal' position, cannot be the "pre-anal" segment, as many publications have claimed. The segment that is bent is the one that carries the procerci and, if I am not mistaken, the latter are always positioned on the last = anal segment of the body. Correct?
If so, any body division visible on Paraphaenocladius larvae between the procerci and the posterior prolegs would have to be a secondary one that is not homologous to true segment borders in the larvae of other taxa. What do you think?"

Ole's reply on the same day was: "I agree with your interpretation of Paraphaenocladius."

Unfortunately, this has not found its way into publications such as the chapter on Orthocladiinae in the new guide to Holarctic larvae (Andersen et al. 2013 in Insect Syst. Evol. Suppl. 66). Thus I am going to propose modifications to corresponding texts in that chapter soon; please see future updated versions of the PDF file offered in this Forum's "Publications" category, "2013 Holarctic larvae manual" board, in the topic entitled "2013 manual on Holarctic larvae -- THIRD printing".

I suspect, but have not investigated, that similar misinterpretations might be affecting diagnoses and key statements for other genera with similarly curved larvae, e.g. Bryophaenocladius, Gymnometriocnemus, etc. Correct segment interpretation may be more difficult for larvae that lack procerci as indicators, but it is always possible to check whether the apparent number of abdominal segments differs from the standard 9.
« Last Edit: May 29, 2014, 08:00:55 AM by Martin Spies »