An elusive genus from the Old World Tropics

While the main emphasis of this blog is on Nearctic braconid wasps attacking caterpillars, from time to time it is nice to expand the geographic coverage. Especially when new information about uncommon species is available to be shared. In this post I will be commenting on the genus Neoclarkinella, described from India in 1996 by Rema and Narendran.

Currently that genus of Microgastrinae comprises three species, two from India and one from China. Those species have been described within the last 20 years or so, and the information on them is extremely scarce, with just seven papers in the scientific literature referring to Neoclarkinella. 

However, the genus is actually quite diverse and spread in the Old World tropics, especially Southeast Asia. In the Canadian National Collection, Ottawa (CNC), I have mounted and studied many specimens (mostly from Thailand, Malaysia, Philippines, China, etc.), representing at least two dozen undescribed species. Many CNC specimens have also been sampled for DNA (CO1 gene) and the resulting barcodes were made freely available recently (in a paper I mentioned in a recent post).

Undescribed species of Neoclarkinella from Thailand, deposited in the CNC (Ottawa), with collection code CNCH2006.

Neoclarkinella can be recognized by the presence of a complete transverse carina in the propodeum (shown in the next figure with a yellow arrow) in combination with a complete median longitudinal carina. Also, the first metasomal mediotergite has a large, rounded depression centrally in the anterior half (usually of a different, paler colouration compared to the rest of the tergite), and the first mediotergite itself strongly narrows towards posterior margin. The specimens I have seen are quite large (for Microgastrinae standards), and might be confused with a group of species of the genus Choeras and specimens of an undescribed genus -all of them relatively common in samples from the Old World tropics.

Undescribed species of Neoclarkinella from Thailand, deposited in the CNC (Ottawa), with collection code CNCH2006. The yellow arrow shows the transverse carina on propodeum.

We do not know much about this genus and its species. Other than its distribution (and potential diversity, as revealed here), we know nothing about their hosts. And the limits of the genus, from a taxonomic point of view, remain unsolved at present.

As far as I know, before this post there were no photographs of specimens of the genus avaiable, but just two line drawings in a 2005 paper describing the second Indian species Neoclarkinella punctata (of authors Ahmad, Pandey, Haider and Shujauddin); and a couple of scanning electron microscope images of the Chinese species Neoclarkinella vitellinipes (of authors You and Zhou) published in 2004 in a book about Chinese microgastrines (Chen and Song, 2004).

Here we have provided the first colour photos of the genus and a brief, simple diagnosis to encourage the search of more specimens of the genus. Hopefully in the near future a study of the many undescribed species would be published...

[This post was written thinking on Dr. Ankita Gupta, an enthusiastic Indian researcher working with parasitoid Hymenoptera and publishing on Microgastrinae from India. I hope you can advance further the study of some of those groups!]