Critter of the Week: The occlupanid – a member of the phylum Plasticae

As we have mentioned many times, new species can be found literally at our door step. But who has found a new species in their pantry?

The secret life of occlupanids

As we have mentioned many times, new species can be found literally at our door step (eg. see Critter of tthe Week 178, a new species under our feet). But who has found a new species in their pantry? Yet, this is the preferred habitat of the secretive occlupanid, a parasitoid on bagged pastries and produce and they are known to disperse through supermarkets and hardware stores among others. Yet, their diversity has not been appreciated to date and the years of research presented by the Holotypic Occlupanid Research Group (HORG) in the USA has only recently started to shine a light on the New Zealand fauna.

HORG presents a fascinating picture of the morphology, taxonomy, history and the complex life cycle of these toothed critters, but highlights that they remain severely under-researched. What is known is that they take nourishment from the plastic sacs that surround the bagged product, not the product itself, as was previously thought. Notable exceptions to this habit are those living off rubber bands and they are particularly known to aggregate in our kitchen junk drawers where they also associate with twist ties, thumbtacks, possibly taking advantage of the accumulated debris known for that habitat.

An unusual gathering of occlupanids, at least two species may be present but we will need to await the final word from world experts.

The New Zealand occlupanid fauna

Occlupanology downunder is still very much in its infancy. While an initial survey of the lower North Island of New Zealand appears to have only uncovered two species, as usual, more questions appear as they are answered. We can confirm that the cosmopolitan toxodentin Palpatophora utiliformis appears to be the most common species, making up nearly 90% of the sampled fauna. However, slight variations in the size of the oral groove may reveal some hidden diversity, which overseas experts will surely be interested in. Maybe this most common species is indeed represented by a species complex, something that will have to be determined in future studies.

Palpatophora utiliformis

The most common of New Zealand occlupanids, a member of the Toxodenta (‘curved tooth’), which comprises some of the more common and most distinctive of class Occlupana. They are identified by having curved processes on the sides of the oral groove, but none in the center. Most species have large palps on their outer sides, giving them a wavy, uneven appearance. According to HORG, Palpatophora utiliformis is “the most distinctive and most common of all occlupanids. Found in nearly every continent through imported processed goods, what was once a parasite of bread products has taken over the planet, thanks to its sturdy palps and squamous shape.”

Palpatophora utiliformis in its typical habitat.
A range of specimens of Palpatophora utiliformis gathered from a number of unrecorded locations around the lower North Island of New Zealand. Note the range of size of the oral groove, possibly indicating some hidden diversity. Maybe this most common species is indeed represented by a species complex, something will have to be determined by experts in future studies.

A new species of Nevani?

The limited ‘OccluBlitz’ revealed one exciting find of a possibly new species. It clearly belongs to the Tridentidae, with the three dental processes within the oral groove but with its small oral groove and dorsal notch it doesn’t match the listed species on HORG. It most closely resembles the Australian Nevani spinustratum and it may represent a sister species of a possible Australasian clade. Nevani spinustratum was found on a survey of an Australian shopping center, attached to a packet of Nevana tomato and cheese pizza bases. Curious for an occlupanid, it was found in a refrigerated niche, and may prefer cooler environments. This New Zealand species was found in the temperate shelf, attached to a Corn Thin, which poses questions whether the Australian species only recently evolved to adapt to colder climates or whether adaptations to temperate climate has evolved a number of times independently.

A new species? Found attached to a New Zealand Corn Thin, this is most closely related to Nevani spinustratum, a tridentid from Australia.

Warning: although harmless looking, these parasites can be dangerous if swallowed by humans and animals. Make sure you dispose of them safely.

Update on the occlupanid discovery - Admordorsum aotearoa

After posting this blog we sent a few specimens over to the Holotypic Occlupanid Research Group (HORG) in the USA and we got this awesome reply from their accessioning department:

Dear NIWA team,

On behalf of everyone at HORG, let me thank you for your generous donation of toxodentids and the precious tridentid holotype. Our archives department is absolutely floored by the dedication and care given to these abiotic specimens. It certainly is a wake-up call for our Archives Department to update their methods! It is truly an honor to house specimens from such a prestigious institution, and with that in mind we are excited to announce the new species name for your corn-clutching tridentid:

Comparing Nevani spinustratum and your specimen, we found some significant differences in not only the unique posterior depression, but in the lateral palps themselves. In addition, within days of receiving your specimen, we also received a similar specimen from the Netherlands, one with a larger oral groove and thicker body, in line with its preferred host: hefty bags of apples. Both of these now comprise their own genus, and we are pleased to add Admordorsum aotearoa to our archives. The genus name, incidentally, was suggested by our Dutch colleague, who submitted the A. groningensis specimens. A truly international effort!