Monthly Archives: November 2011

New paper on Colombia on its way

It seems as if nothing happened during the past three weeks. Less is true. Just returned from Cincinnati where I worked together with Francisco Borrero on our next Colombian paper (Drymaeus and Stenostylus).

Drymaeus is a genus with many, many species, with hundreds of names available throughout its wide range from Argentina to the southern USA states. The current division in two subgenera, Drymaeus s.str. and Mesembrinus, urgently needs a revision as they simply contain too many taxa to be natural groups. Ongoing morphological and molecular studies will be needed to solve this ‘systematic mess’.     

About 150 taxa in this group have been associated with Colombia. On morphological grounds alone, we were able to reduce this number to about 100 (of which several undescribed species), plus a number of morphospecies for which insufficient data are available to assign them to known taxa.

Anyway, this whole exercise gave us a better understanding of the diversity in this group. It also allows me to make some corrections on previous assignments (after all, in philosophical sense, our understanding of species are merely hypotheses to be tested by new observations). 
One example is Drymaeus (D.) murrinus (Reeve. 1848). This species was described from “Santa F?? de Bogota” and is generally recognized in collections from several regions in Colombia. Here are some photographs of what I identified as D. murrinus in an earlier blogpost, found near Bogot??. 

Screen_shot_2011-11-03_at_11

Reeve, who is known to have accurately figured species in his ‘Conchologica Iconica’ (but seen my recent paper with Jonathan Ablett in ZooKeys on the Cuming collection), gave two figures for this species (figs 273 a, b).

Screen_shot_2011-10-19_at_20

When I studied the London type material, I only found one specimen; it matches the right-hand figure, while the left-hand figure given by Reeve shows the same colour pattern as the shell in the upper figure above.
Studying the variation in the material of species from Colombia, we discovered during the past weeks that both figures of Reeve represent two species. The right-hand figure is the ‘true’ Dmurrinus (selected as lectotype by me in an earlier paper); the left-hand figure is one of colour morphs of D. convexus (Pfeiffer, 1855), a species which is wide-spread around Bogot?? but only occurs in Cundinamarca and Boyac??. The shells pictured above are thus D. convexus. We have been unable to recognize the ‘true’ D. murrinus in the material studied from Colombia.
Advertisements