Species Profile: Lesser Vlaspipe

The impenetrable cloud forests of the Suiyue archipelago were one of the last places to be explored in Dome 4; the first two teams that ventured beyond its crutchtree mangroves never returned. However dangerous the islands were, they became a subject of fascination for all. The now infamous Wray tapes from the first Suiyue expedition document arboreal sprinters brachiating with their tongues, migrating riverine jetleeches, grazing social shellsnakes, and what is presumably a giant flightless iactocaud that ended the transmission by ripping the camera and accompanying crew to shreds. Drone expeditions have not yet rediscovered any of the Wray fauna, implying that they lie further inland than our current battery lifespans last for, but less flashy relatives have been found along the coastal rainforests.

Of these includes the lesser vlaspipe (Crassophis fallax), a smaller folivorous relative of the colossal Wray vlaspipe. Just like its cousin, adult lesser vlaspipes do little but eat. In spite of their rotund and heavy bodies, their iron grip on branches makes them surprisingly adept climbers, utilizing a mix of concertina locomotion to move between branches and straight slithering like a Gabon python when on a branch. Both because of physical limitations and their glacial metabolism, vlaspipes climb rather slowly. This is likely an adaptation to cope with the scarce nutrients its diet provides.

When feeding, lesser vlaspipes will often anchor themselves using the posterior end of their bodies which allows them to strip a branch bare before moving on. Vlaspipes will only fit boluses of food into their true jaws after they masticate it with their external horizontal maxillipeds. Though in ancestral placophids, these were arms used for climbing, as the muscular strength of their soft abdomens grew, these arms found a new use in prey capture and were eventually co-opted into the oral system. Maxillipeds take a wide range of forms between clades, though the most common are the trap-jaw archetype in southern shellsnakes and asymmetrical archetype in northern shellsnakes. The lesser vlaspipe belongs to the latter category, exhibiting an exemplarily basal form with the only asymmetricity being the ‘teeth’ of the maxillipeds in a shape complementary to each other and strikingly convergent to Oniscidea isopods on Earth. If these morphological similarities translate to similarities in usage, then the evolution of asymmetrical jaws likely had to do with increasing the surface area of their bites. This would not be surprising, considering that most asymmetrically jawed placophids are herbivorous, durophagous, or scavenging, all lifestyles that benefit from a good ability to chew.

Using drone measurements, a typical lesser vlaspipe is about 80 cm in length when fully stretched out. Older specimens are often larger, reaching up to 90 cm, while the smallest was an individual we documented off the southern stretch of Serna’s Island at just 63 cm. Throughout the 6 months we spent watching vlaspipes, we found not even one smaller. It was as if they were born as adults. This begs the question – where are the least vlaspipes?

Some weeks ago, a separate team investigating hybridization in placophids sent us a video of a lesser vlaspipe being courted by a tri-banded sporeguide, a slender frugivorous shellsnake which specializes on the fertile stems of various horsetail trees. Unlike previous occurrences of cross-species mating involving tri-banded sporeguides where the female of the other species resisted, resulting in the sporeguide realizing its mistake and slithering away, the female vlaspipe eagerly accepted the sporeguide. The researchers told us that they believe this represents a closer phylogenetic relationship between the sporeguides and vlaspipes than had been thought and asked if we had ever observed any vlaspipes eating fertile stems or other behavior that could be plesiomorphic to the common ancestor of the two clades.

That was when something hit me: sporeguides in hybridization scenarios have only been observed as males, and vlaspipes as females. What is to say that they are not different sexual morphs of the same species? Mosquitos, after all, have nectivorous males and bloodsucking females.

As vlaspipes and sporeguides are both found in coastal forests, we decided a short trek into Serna’s Island would not hurt. Over a few days, we managed to capture 3 lesser vlaspipes and 8 tri-banded sporeguides along with a dozen different epiphytic rhacophytes our engineer brought back. Genetic sampling revealed that our theory had been correct. This explains one half of the question, as sporeguide juveniles had been found and indeed captured, but still does little to answer where the juvenile vlaspipes are.

We decided to release most of the sporeguides but kept the largest ones along with the two vlaspipes, hoping they would breed in captivity. As spring turned to summer, the appetites of the sporeguides grew insatiable. We continued regular expeditions to gather fertile stems for the sporeguides. Despite their affinity for eating, the sporeguides only seemed to look worse with every passing day, with their bands beginning to fade, usually a sign of ill health. This was not helped by the fact our vlaspipes had died from mysterious causes concurrently. Onana theorized that they had been targeted by an endoparasitoid omenfly, a clade of thriae which lay their eggs in bipods, and that in a few weeks’ time they would shrivel up into a cocoon from which adults would emerge. No matter how macabre, placophid-targeting omenflies had never been documented before, so we decided to bite the bullet and see what comes out.

Weeks turned to a month and the sporeguides had become bloated and sluggish. They now neared their end, even rejecting the fertile stems we provided. Soon thereafter they died, to nobody’s surprise.

We waited for the omenflies to emerge, but they never did.

Was it some sort of other parasite? We dissected the least putrefied specimen we had – there was nothing out of the ordinary, nothing apart from a pair of ovaries. The sporeguides were not sick, they were turning into vlaspipes through sequential hermaphroditism.