A Whopping 71 New Species of Parasitoid Wasps Have Been Described

Parasitoid wasps, which generally inject their eggs into a host like a caterpillar, are some of the coolest examples of just how specific the process of evolution can be. Whether it's because of the sheer sci-fi potential of larvae eating their way out of a host, or due to the complex evolution of the chemicals the wasps secrete to prevent a host's immune system from fighting back, parasitoid wasps are crazy cool. And now, according to research published in ZooKeys, zoologists have described 71 new species of one of the least studied genera of parasitoid wasps.

The whole paper is available online, which rules, but considering it contains high-res photos and descriptions of 90 different species in the genus Oxyscelio, it's positively massive. The goal of the work was to survey the genus, which was first described by Kieffer in 1907 and which had very few new species described since the early 20th century. Oxyscelio is part of the family Platygastridae, a massive family of parasitoid wasps, and has a rather huge range, covering equatorial Africa, southeast Asia, and Oceana.

Thus, it stands to reason that there were likely a few new species to find out there. Still, this survey led by Roger Burks at Ohio State produced incredible results: 19 previously-known species were redescribed and confirmed, and 71 entirely new species were added to the genus.

It all makes for a fascinating look into strict zoological work, in which the animals we find are classified, argued over, and reclassified until a consensus is reached. When it comes to small wasps that all look fairly similar, classification can be truly difficult. Before we look at some of the wasps (warning: there's no way in heck I'm going to talk about all of the wasps, check the paper for that) I want to quote from the authors' introduction, which describes the convoluted zoological history of Oxyscelio:

The genus was first erected for a single species from Indonesia, Oxyscelio foveatus, by Kieffer (1907), which he later treated as a subgenus of Chromoteleia Ashmead (Kieffer 1910a) but later raised again to generic rank (Kieffer 1926). Following its original description the status of Oxyscelio and the genera that surround it was particularly confusing. This is clearly evident in the fact that, other than the type species, all taxa described prior to 1930 that are currently accommodated in Oxyscelio were described under other generic names. This situation was resolved by Dodd (1931) who recognized a range of species from the Oriental and Australian regions as being congeneric based on several key characters, the form of the fore wing venation (outlined above) and the structure of the metanotal plate. In so doing he treated Dicroteleia Kieffer, Camptoteleia Kieffer and Xenoteleia Kieffer as junior synomyms of Oxyscelio, and transferred 32 species to that genus including all Australian taxa that he had preciously described under Sceliomorpha Ashmead (sensu Kieffer 1926). This work by Dodd (1931) and his other studies on various scelionid genera around that time provided significant taxonomic stability and are testament to his thoughtful and perceptive approach to discriminating genera and species.

But since the 30s, only three new species in the genus were described. The work of Burks and his colleagues—Lubomír Masner, Norman F. Johnson and Andrew D. Austin—has thus brought a whole lot of clarity to an understudied genus. So much, in fact, that this paper is only the first of three papers reporting on the team's findings, with a focus on Indo-Malayan and Palearctic species. Finally, let's take a peek at a few species that I admit I pulled out completely at random:

This lovely lade is O. sinuum, a new species found in Thailand. It shares a complete occipital carina (a ridge at the base of the head) with other species, but is distinct for having a flat, rugose metascutellum (a part of its thorax). Like all of the species describe, O. sinuum is tiny—the scale on the images is listed in millimeters.

This here is O. vadorum, which was found in Sri Lanka. According to the authors, "Even though only a single, damaged specimen is known, this species is described because of its many unusual character states, including the chiefly granulate gena." (The gena is a part of the exoskeleton that borders the eyes.)

This is O. vittae, which was found in the Philippines and yet another new species. I chose this female because the depressions around its exoskeleton are really cool looking. (We can't be technical all the time!)

This here is O. aureamediocritas, another new species found in evergreen forests in Thailand. It's notable for the prominent ridge/groove on the front of its face, its enormous compound eyes, and its coloration.

Let's close out with O. angustifrons, whose rather meaty antennae (fig. 25) I found fascinating. This new species was found in Indonesia and Brunei.

So there we have it: A ton of new species described in exhausting physical detail. It's not often that rote zoology makes headlines, and it's for the same reason that I admittedly struggled at times when I was studying it: all of the incredible taxonomic precision doesn't easily translate into a narrative. I don't blame you if you looked at all these pictures and thought "Sure, this specimen's antennae look kinda different than that one's. But where do they live? How do they live? How rare are they?"

But, at the same time, the above photos are stunning, and they represent a brain-melting amount of work. Just imagine: Four researchers scoured half the world looking for obscure wasps in the hopes that after hours and hours of staring at them under microscopes to note even the most minute differences, they'd then be able to write those differences down, publish them, and prove that a genus that hasn't garned much attention in 80 years is far more vibrant than previously thought.

All of that work was done, not to impress the tiny fraction of the human population that was ever concerned about the speciation of parasitoid wasps from anything more than a macro, cool YouTube video kind of way. Instead, like so many researchers around the world, this team took on an incredible amount of work simply to set the record straight and increase the body of knowledge about life on our Earth. Is the work almost impossibly dense? Sure, if you want to look at it that way. But it's also representative of the lengths we'll go to catalog the Earth, which to me is the most admirable part of science.

@derektmead