New publications - New species of Schikhobalotrema (Digenea: Haplosplanchnidae) and a note about Menemerus bivittatus (Araneae: Salticidae)

I'm happy to report I've got two new publications that have come out this month. The first was a long time coming, and includes a molecular phylogeny for the poorly studied digenean family Haplosplanchnidae. I also described a new species in the paper, Schikhobalotrema huffmani which I was very pleased to name after my friend, mentor and masters degree supervisor at Texas State University, Dr. David Huffman. No one deserves the honor more than him. Here is the citation and a link to the paper:

Huston, D.C., S.C. Cutmore, and T.H. Cribb. 2017. Molecular phylogeny of the Haplosplanchnata Olson, Cribb, Tkach, Bray and Littlewood, 2003, with a description of Schikhobalotrema huffmani n. sp. Acta Parasitologica, 62: 502–512. PDF on Researchgate. 

This family has barely been studied on the Great Barrier Reef, even though its looking like the group is a bit more diverse than we thought (more on that coming soon!). There are actually only two species of Haplosplanchnidae reported from the GBR, so this beast makes the third.

Schikhobalotrema huffmani from intestine of Tylosurus crocodilus, Lizard Island, Great Barrier Reef, Australia. A) Dorso-ventral B) Lateral C) Terminal Genitalia

I also included the first record for the species Haplosplanchnus pachysomus from Australia in the same paper. Here's a picture of the worm for your admiration:

Haplosplanchnus pachysomus from the intestine of Mugil cephalus, Moreton Bay, Australia

Parasites are pretty groovy but I'm also a bit of an amateur entomologist, and have published a few short papers and research notes on insects over the last couple years. I just got a short note published in the Australian Entomologist detailing some observations I made of a species of jumping spider, Menemerus bivittatus on the balcony of the old "Queenslander" style home I rented when I first moved to Brisbane. If you don't live in Brisbane, essential background information is that all our homes are infested with these tiny black ants called Technomyrmex sophiae. These critters aren't that much of a problem, and don't really get into your food or anything, but they will build nests in just about any small crevice. They seem to enjoy potted plants the best, but I have personally experienced small colonies living inside the machine bits of a blender, and behind the motherboard of my washing machine. The point here is, they are constantly moving house, and their little wagon trains are great targets for raiders.

Menemerus bivittatus is a pan-tropical species and is pretty common around here in Brisbane. We had them back in Texas as well, which is why they were so easily recognizable to me. Anyway, these spiders have some clever tricks. One such trick is train robbery, stealing the ants' precious larval cargo. The micro-world is a savage one. Check out the video I shot of this behaviour on YouTube.

Be sure to download the paper and give it a read. Heres the citation and a link:
Huston, D.C. Train Robbery: Menemerus bivittatus (Dufour, 1831) (Araneae: Salticidae) steals larvae of Technomyrmex sophiae Forel, 1902 (Hymenoptera: Formicidae) in transit. Australian Entomologist, 44: 85–88. PDF on ResearchGate.

 

Fieldwork in French Polynesia

Parasitology isn’t always glamorous, but I find it comes with perks. I just got back from a month of fieldwork in French Polynesia, and it was awesome.

Approaching Moorea, French Polynesia on the ferry from Tahiti

 

 

 

 

Along with two other students from my lab, I was lucky enough to be invited over by Dr. Pierre Sasal to work on a project examining the parasites of three species of important aquaculture fish in French Polynesia: Chanos chanos, Siganus argenteus, and Platax orbicularis. While we were there we also had plenty of time to collect fish for our own research projects. For me that meant fish of the families Acanthuridae and Kyphosidae. I was also pleasantly surprised to get some interesting trematodes in the family Atractotrematidae from Chanos chanos and Siganus argenteus.

A beautiful Naso vlamingii I collected off Rangiroa in the Tuamotus. Species of Acanthuridae in the genus Naso have some very interesting haplosplanchnid trematodes that I am currently working on.

We spent our first two and our last week at the CRIOBE research facility in Moorea, a small island just off Tahiti.  Moorea is stunningly beautiful, and the water is warm and clear.  If you ever get to visit, be sure to try the local fruit juice. Baguettes are a given.

The bay we set out from each day on our way to the reef.

 Our third week was spent in Rangiroa, a large atoll in the Tuamotus. This place was far out.

Pretty sure I could live here

Although the trematode fauna of French Polynesia is relatively depauperate compared with the Great Barrier Reef, I was still able to make a pretty good collection.  I’ve got a lot of projects on my plate right now, but hopefully I’ll get around to working up my French Polynesian collection soon. French Polynesia was among the most beautiful places I’ve ever been, and being able to spend a month collecting there was a privilege I won’t soon forget.

 

The Life-cyle of Gorgocephalus yaaji (Digenea: Gorgocephalidae)

The complexity of trematode life-cycles was really what first drew me in and fueled my worm obsession.  Thus, I am pleased to say that I have a new paper hot off the press, in which my co-authors and I elucidate the first full life-cycle for a species of the family Gorgocephalidae.  I recommend that you read my paper immediately:

"Huston, D.C., S.C. Cutmore and T.H. Cribb. 2016. The life-cycle of Gorgocephalus yaaji Bray & Cribb, 2005 (Digenea: Gorgocephalidae) with a review of the first intermediate hosts for the superfamily Lepocreadioidea Odhner, 1905. Systematic Parasitology, 93: 653-665." have a quick read on Readcube or go straight to researchgate PDF

The three species that comprise the Gorgocephalidae are true to their namesake (relatively), with little tentacles sticking out of their oral sucker. I reckon they look quite a bit like Graboids from that awesome movie Tremors.  Tremors was one of those flicks which nurtured my love of cheesy monster movies.

The family Gorgocephalidae didn't start out as a family. It was first erected by the American trematodologist H.W. Manter in 1966 as a subfamily of the Lepocreadiidae. Manter called his new subfamily the "Gorgocephalinae" which he created to accommodate the type species, Gorgocephalus kyphosi.  Manter had recovered these odd little worms from the silver drummer Kyphosus sydneyanus which had been caught by Robert Piddington off Adelaide, South Australia.

Gorgocephalus kyphosi Manter, 1966.

Not much happened in regards to these strange worms for some time, though greater glory was destined. In 1971 the most influential trematode taxonomist of all time, Yamaguti, took a look at a couple of Manter's paratypes, and thought they were more unique than their pitiful subfamily designation suggested. The little tentacle mouthed worms finally got that family rank. And so began the Gorgocephalidae Manter, 1966.


Nearly twenty years passed before another gorgocephalid was discovered. In 1983, a second species was described by the Russian trematodologist E.V. Zhukov from Kyphosus sectatrix off of Cuba.  I have never been able to find much information on Zhukov, likely due to majority of his work being published in Russian.  Based on the dates of his Cuban publications however, It looks like Zhukov was in Cuba before the fall of the Soviet Union. However, regardless of the tensions between the USA and the Soviet Union, Zhukov named his new species Gorgocephalus manteri in honor of Manter's contributions to the field.

In 2005, Rod Bray and Tom Cribb described the third (and currently final) species of gorgocephalid from Kyphosus vaigiensis off of Lizard Island on the northern Great Barrier Reef.  They called this species Gorgocephalus yaaji. 

Another ten years passed.

Then, in 2015, something new happened.  During a study of the intramolluscan trematode fauna of the banded periwinkle Austrolittorina unifasciata (Littorinidae) from along the south coast of Australia, O'Dwyer et al. (2015) discovered and described the first known cercariae of the family Gorgocephalidae.  They were able to confirm that these intramolluscan stages belonged to a species of the family based on 28S rDNA sequence data.  While a previous sequence existed for Gorgocephalus kyphosi (Olson et al. 2003) from Lizard Island, O'Dwyer et al. determined that their cercaria most likely represented a separate species, based on differences in the sequence data.

Now, I had just read O'Dwyer et al. (2015) before my first trip to Lizard Island.  This was also my first trip to the Great Barrier Reef, and after my many years working in the freshwater systems of Texas, research in a coral reef ecosystem was exciting and unique.  My original goal for the trip was to study the intramolluscan trematode fauna from gastropods of the family Cerithiidae. However, I found cerithids quite difficult to find.  In fact, I was only able to collect one species in large numbers, Rhinoclavis vertagus.  I began to understand that the trematode fauna of Great Barrier Reef cerithids might be a rather difficult topic, so in frustration I turned my attention to some gastropods that were a bit more common in the area, littorinids.

To keep the narrative of my serendipitous discovery brief, I collected and examined some specimens of Echinolittorina austrotrochoides from the rocks along the beach. By placing these little snails into little cups of seawater, I was able to induce natural emergence of some cercariae, which just so happened to look just like those described by O'Dwyer et al. (2015)!

Larval stages of Gorgocephalus yaaji. A) Cercariae; B) Rediae; C) Metacercariae encysted on algae. From Huston et al. (2016).

It had previously been speculated that the metacercariae of gorgocephalids would be associated with algae due to the algivorous nature of the kyphosid host fishes.  I tested this by placing my cercariae in little cups of seawater with some algae.  They happily obliged, and encysted on the algae within a few hours.  The route of gorgocephalid recruitment into kyphosids was confirmed.

Back in the lab, I generated ITS2 and 28S rDNA molecular sequence data from the cercariae as well as from adult gorgocephalids we collected from Kyphosus cinerascens during the same trip. This allowed me to confirm that the larval stages did indeed belong to Gorgocephalus yaaji.  From there I wrote up a manuscript about the life-cycle, and included a review of the gastropod-trematode relationships for the superfamily Lepocreadioidea.  This review led to some fairly interesting insights, though a discussion on those insights is a bit beyond the scope of this post.  I'll write another post about the other half of the paper some time in the indeterminable future!

References

Bray, R. A., & Cribb, T. H. (2005). Gorgocephalus yaaji n. sp (Digenea: Gorgocephalidae) from the brassy chub Kyphosus vaigiensis (Perciformes: Kyphosidae) off Lizard Island, northern Great Barrier Reef and further records of G. kyphosi. Zootaxa, 1068, 39-46.

Olson, P., Cribb, T., Tkach, V., Bray, R., & Littlewood, D. (2003). Phylogeny and classification of the Digenea (Platyhelminthes: Trematoda). International Journal for Parasitology, 33, 733-755.

O’Dwyer, K., Faltýnková, A., Georgieva, S., & Kostadinova, A. (2015). An integrative taxonomic investigation of the diversity of digenean parasites infecting the intertidal snail Austrolittorina unifasciata Gray, 1826 (Gastropoda: Littorinidae) in Australia. Parasitology Research, 114, 2381-2397.

Manter, H. W. (1966). A peculiar trematode, Gorgocephalus kyphosi gen. et sp. n. (Lepocreadiidae: Gorgocephalinae subfam. n.), from a marine fish of South Australia. The Journal of Parasitology, 52, 347-350.

Yamaguti, S. (1971). Synopsis of digenetic trematodes of vertebrates. Keigaku Publishing Co. Tokyo, Vol I, 1074 pp. Vol II, 349 plates.

Zhukov, E. (1983). New representatives of the fauna of trematodes from the fishes of the Gulf of Mexico. Parazitologiia, 17, 112-117.

 

The Adventures of the Integrative Ecologist: Hunting for worms in Adelaide

I was recently in Adelaide, South Australia, after a particular species of trematode, Gorgocephalus kyphosi, which I need for some of my molecular work.  I would have written a blog post about it, but fortunately for me, Rebecca Wheatley beat me to it:

The Adventures of the Integrative Ecologist: Hunting for worms in Adelaide: A few weeks ago, I went hunting for worms. Funky worms. Gorgocephalids, in fact – pronounced gor-go-kefalids , they're a family of d...

The secret life of the Enenteridae: new species and unknown life-cycles

I was recently awarded a small scholarship through the University of Queensland's Moreton Bay Research Station in partnership with Sibelco Australia. The scholarship is intended to support my research in the waters of Moreton Bay on a little known family of digenetic trematodes called the Enenteridae.

With few exceptions, the sexually mature stages of species of the family Enenteridae parasitize only one host group, marine fishes of the family Kyphosidae (the drummers or sea chubs).  I've discovered a few new species of the genus Enenterum from kyphosids in Moreton Bay, and am currently in the process of describing them.

A selection of illustrations of species of the family Enenteridae. Illustrations from Bray & Cribb, (2002) and Bray (2005).

The scholarship is also intended to fund an additional project, elucidation of the first life-cycle of an enenterid.  This will be the real challenge, as a first intermediate host for the family has never been discovered.  I have a few leads to follow up on, but I'm still going to need a lucky break!

References:
Bray, R.A., & Cribb, T.H. (2002). Further observations on the Enenteridae Yamaguti, 1958 (Digenea, Lepocreadioidea) of the Indo-West Pacific region, including a new species from Western Australia. Acta Parasitologica, 47, 208-223.
 

Bray, R.A. (2005). Family Enenteridae Yamaguti, 1958. In: (Eds. A. Jones, R.A. Bray and D.I. Gibson) Keys to the Trematoda. Volume 2. Wallingford, CABI Publishing and the Natural History Museum, pp. 657-661.

Hunting Haplosplanchnidae on the Great Barrier Reef

Early in 2015, just about a month after I arrived in Australia, I had the good fortune to visit Lizard Island on the northern Great Barrier Reef (GBR).  My goal while I was there was to collect gastropods in order to begin the task of elucidating trematode life-cycles on the GBR.  A separate goal was to build up a collection of trematodes of the family Haplosplanchnidae from fishes of the family Acanthuridae (includes the surgeonfishes, rabbitfishes, and unicornfishes).

Haplosplanchnids seem to be well concentrated in herbivorous fishes, so the family Acanthuridae was a good choice.  I spent most of my efforts on surgeonfishes and unicornfishes.  So my mornings were spent spearfishing for these guys, with my afternoons and evenings spent dissecting them.

I'll probably make a longer, and much more scientific post about Haplosplanchnids some day soon, but for now I'll just link to a video of me on Lizard Island talking about my purpose there.

Monitoring and Marking Techniques for the Comal Springs riffle beetle Heterelmis comalensis

I continue my self promotion:

Huston, D.C., J.R. Gibson, K.G. Ostrand, C.W. Norris and P.H. Diaz.  2015. Monitoring and marking techniques for the endangered Comal Springs riffle beetle, Heterelmis comalensis Bosse, Tuff, and Brown, 1988 (Coleoptera: Elmidae). The Coleopterists Bulletin, 69: 793-798.  PDF

This was the second paper that I worked on that involved the endangered Comal Springs riffle beetle Heterelmis comalensis.  I discussed the natural history of the beetle and its endangered species status, as well as our attempts to culture them in the laboratory in my previous post.

The goal of this particular project was to evaluate various methods for monitoring the population size of H. comalensis at Comal Springs in New Braunfels, Texas.  Two methods were tested: (1) the use of paint for a mark recapture pilot study and (2) using the "cotton cloth lure" technique for trapping.

As you are likely aware, mark-recapture methods are relatively straightforward.  You capture a group of animals, give them some sort of recognizable mark or tag, release these animals, and then recapture these animals at a later time.  The information obtained can help estimate population size and dispersal of the animals you are studying.  Well, in the end it turns out that marking tiny aquatic beetles isn't really that easy.

While there is a good amount of published literature available about marking terrestrial insects, very little work has been done in terms of marking aquatic invertebrates.  Most of the difficulties inherent in marking an aquatic invertebrate are obvious, I.E. water soluble paints won't work, paper tags will be destroyed, glue will dissolve, etc. etc.  This becomes even more complicated when you consider individuals which live in riffle environments, as these abrasive habitats can damage and obscure even water resistant tags (Freilich, 1989).  Whatever to do?  Well Wineriter and Walker (1984) did an evaluation of various marking methods for insects, and they recommended the use of water insoluble paints.  That seemed the best option, so oil-based paint pens were acquired for the job.

Now of course we couldn't just go about slapping paint willy-nilly on our endangered beetles.  I mean what if we poisoned a bunch of the little guys to death?  Killing a bunch of endangered species on accident means paperwork, so we needed a surrogate for the test.  Fortunately, a related species of riffle beetle, Heterelmis vulnerata, is relatively common and widespread in Texas and is around the same size, thus H. vulnerata seemed a good match for the surrogate.

In order to give these tiny (~2mm) aquatic beetles a mark, the following procedure was devised.  Beetles were placed in a water filled tray, with a nylon mesh placed on the bottom.  The beetles like to cling to things, so they always grab onto the nylon mesh.  Then a small drop of paint was liberated from the paint marker into a little blotter.  The mesh was then pulled from the tray and the elytra of beetles were carefully dried with a cotton swab.  Then, using an insect pin placed in a pin vice, a tiny dab of paint was placed on the beetle.  The beetle was then kept out of the water for a minute or so as the paint dried, before being returned to the water. Clearly this wasn't the easiest thing in the world.  You needed to have these beetles dry long enough for the paint to dry, but not so long as for the beetles to die.

Marking Heterelmis vulnerata with oil-based paint using an insect pin in a pin vice. Photo courtesy of J.R. Gibson

After some 20 days, none of the marked or unmarked H. vulnerata had died.  Thus it was thought that the procedure would be safe for H. comalensis in the field.  

So in the field, 100 beetles were collected and separated into 10 groups of 10 with each group being marked with a different color.  After one month only a single marked beetle was re-captured 1.7 M from its original release site.  The second month only a single beetle was re-captured (though a different individual) at its original site of recapture.  I'll cut through the long-winded part of the discussion and say that what this really told us was that the marking techniques would be difficult in the field, but they do have the potential for showing that dispersal is very low for individual H. comalensis.

The other part of this project was the temporal evaluation of the "cotton cloth lure" method.  So what is the cotton cloth lure (CCL) method?

Essentially this methodology was pioneered for the Comal Springs riffle beetle by my colleague and co-author Randy Gibson.  Randy once said that he developed the method based on some techniques used by cave biologists.  Apparently these cavers would throw old mop heads down into cave pools.  As the mop heads decomposed, biofilms would grow upon mops and it would attract cave invertebrates which could be captured when the mop heads were retrieved.

In the CCL method for riffle beetles, pieces of cotton/nylon sheet are cut into squares, folded up, and buried in the interstitial gravel habitats surrounding spring openings and upwellings.  Again, biofilms will grow on the cotton as it decomposes, which seems to attract grazers like riffle beetles.  This method also attracts multiple other species including the common riffle beetle Microcylloepus pusillus and ocassionally the endangered Pecks Cave amphipod Stygobromus pecki and the endangered Comal Springs dryopoid beetle Stygoparnus comalensis.

The goal here was to watch these lures over a long period of time (17 weeks) and see if the "capture" success varied.  Presumably, if part of the lure was decomposing, eventually there would only be inert fibers left, upon which the lure should no longer be useful.  Furthermore, perhaps there would be a peak time in which the lure was the most attractive to H. comalensis (meaning capture success was highest).

Again, I'll cut through the long winded discussion and just show the graphical results:

Three cotton cloth lures (A,B,C) buried 1 M apart from one another in Comal Springs for 17 weeks and the number of Heterelmis comalensis beetles found on each lure during each weekly sampling effort.

As you can see from this graph, it looks like capture success for H. comalensis is best between 7 and 10 weeks after the deployment of lures.  My presumption is this is when the biofilm fauna has really begun to flourish, and there is lots of good food available for the beetles.  Also, it looks like the capture success drops off rather rapidly after 10 weeks, presumable after all the organic matter is gone and only the inert nylon fibers remain.

In conclusion: This project was a pretty useful pilot study into the best methodologies for evaluating Comal Springs riffle beetle population sizes.  The lure method still remains the best technique, because it is minimally damaging to the habitat and beetles are able to be returned alive at the site of capture.

References:

Freilich, J. E. 1989. A method for tagging individual benthic macroinvertebrates. Journal of the North American Benthological Society 9: 351–354.

Wineriter, S. A., and T. J. Walker. 1984. Insect marking techniques: durability of materials. Entomological News 95: 117–123.