Recent news on the snail story …

It’s March, and we’re on to Blog 3, so still going strong. Continuing with the current theme of marine gastropods, we’ve just had a new piece that recent master’s graduate (and now PhD candidate) Stephen has had published. We still have to get onto a discussion of his masters thesis, but that will come in time!

Stephen’s third paper was published in Zootaxa, and evaluates the taxonomy of marine snails belonging to the genus Laevistrombus (Fig. 1). After the first major revision of the family Strombidae (Abbott 1960), Laevistrombus was considered monospecific (that is, only one extant species in the genus). This is where we could have a whole discussion on whether to lump or split organisms into distinct species. Abbott (1960) was a lumper, whereas recent revisions on this genus have considered Abbott (1960) to have been too conservative. While later authors suggest that there are three extant species, we suggest that further splitting is needed, proposing that L. taeniatus and L. vankorensis be elevated to species. We provide descriptions on the morphology and distribution to do this.

Fig. 1. The five extant members of the Laevistrombus: A) L. turturella; B) L. taeniatus; C) L. guidoi; D) L. canarium; and E) L. vanikorensis

Fig. 2. Morphology of a snail

We provide the description of five species of Laevistrombus in the paper. For each, we provide the taxonomic identification, the definition, type locality and distribution. We also identify the type material. Comparative analyses of this complex have been problematic specifically because there has been a lack of designation of the type material.  The shells of these animals are quite beautiful (Fig. 1). They are smooth, solid and quite round. The outer lip is quite thick and smooth, becoming a bit harder and rougher (calloused) towards the head region. The columella (the spiral bit that goes through the middle, Fig. 2) is smooth and thickened in the middle. To see what makes each of these species different, you can check out the paper by clicking on the link under List of Publications.

Hopefully you can see that there’s a lot more to marine snails that you probably thought. And there will definitely be more to come in the future. I think one of the most important lessons out of this paper is that lumping or splitting is perhaps a matter of opinion when there isn’t solid evidence or appropriate descriptions. If you state specifically why you think something is different to something else, and you provide evidence to support that observation, then there is no ambiguity in your rationale for splitting or lumping. However, if you just say that things look alike, and lump them together without taking a holistic view, then you introduce ambiguity, which causes confusion. 

You can read more about my research in my publications, listed on my blog. You can also find me on ResearchGate, the JamesCook University website and Twitter.

Snail tales continued …

So far so good. It’s February, and we’re on to Blog 2. I’m going to continue on the current theme of marine gastropods, moving on to a second piece that my master’s student Stephen completed. Stephen has just completed his masters, which warrants discussion itself, but more on that another time!

Fig. 1. Priabonian age (Ma = millions of years ago)

Stephen’s second paper was accepted in Paleontological Journal, and describes a new species of Paraseraphs from the Priabonian (37.8 – 33.9 Ma; Fig. 1) white limestone formation of Jamaica. Paraseraphs are extinct gastropods, so perhaps you’re wondering why it’s important that this paper was published. Well, really the only way that fossils can be designated to species is morphologically. However, there is a risk in saying that two animals are the same species just because they look the same. In this paper, while we used morphology, we also looked at the spatial and temporal distribution of the species in relation to others.

The description of Paraseraphs cantamessae is based on morphology (Fig. 2). It has a slender shell with slightly concave whorls, and there is distinct elongation of the shell on later whorls. The base of the shell is anteriorly quadrate. The shell spire is acute and the sutures are well defined. While it occurred sympatrically with another species, P. procerum, P. cantamessae is cylindrically elongated, larger, and more dorsoventrally convex. Two additional species occurs in the region. However, they are separated temporally from P. cantamessae. Both P. texanopsis and P. erratica occurred roughly 47.8 - 41.2 Ma (Lutetian). Several other species are morphologically similar to P. cantamessae, but they are separated both spatially (P. armoricensis and P. propedistortum occurred in Europe) and temporally (41.2 – 37.8 Ma and 47.8 - 41.2 Ma, respectively).

Fig. 2. Type material for Paraseraphs cantamessa sp. nov.: (a) holotype USNM, no. 135097A; (b) paratype USNM, no. 135097B; (c) paratype USNM, no. 135097C. (Details and image taken from publication: Maxwell et al. 2018)

So, there you have it. Hopefully you now know even more than you did from the last blog. I think one of the most important lessons out of this paper is that we shouldn’t just think that one species conception is the answer to everything. If we just used morphology in this instance, all the fossils might be considered one species. However, if we take into account other factors, like spatial or temporal distributions, we can begin to see that things might be a little more complicated than they originally appeared. By taking a look at the organism in context, we gain a greater understanding about how it lived in relation to other organisms. 

You can read more about my research in my publications, listed on my blog. You can also find me on ResearchGate, the James CookUniversity website and Twitter.

Let’s start again …

It seems that this is something that happens yearly. I start with good intentions of trying to blog, which lasts a few months and then withers to nothing as work takes over. So, I’m going to just keep on trying and hopefully sometime it will stick and become more of a routine.

So, what approach should I take this year? Well, I thought I might update you on some of my recent works. Let’s start with a look at snails.

Fig. 1. The three extant members of the Terebellum. 1)  T.  terebellum (A-H). 2) T. delicatum (I-K). 3) T. hubrechti (L-M). (Image taken from publication: Maxwell et al. 201

So, my master’s student, Stephen has been working hard, and recently submitted his thesis for examination. He’s recently had a paper accepted in Proceedings of the Royal Society of Queensland, which provides a revision of Terebellum delicatum Kuroda and Kawamoto in Kawamoto and Tanabe, 1956 (Gastropoda, Seraphsidae). One of the primary purposes of this review was to give a higher level of taxonomic clarity, as there are at least three species of Terebellum that can be confusing to distinguish (Fig. 1). Although the paper hasn’t come out online yet, it’s a happy achievement all round.

Fig. 2. Contrasting T. terebellum and T. delicatum (Image taken from publication: Maxwell et al. 2018)

T. delicatulum’s (Fig. 2) new description is based on morphology, particularly colour. Generally, the shell has a base colour of tan, with circular white spotting. A single dark spot, smaller than each larger one, can be observed within each large white one. The resulting outcome is a white crescent shape that partially surround the darker spot. The axial ridge in the middle of the columella is also thickened, and white, being roughly 7-9mm long. However, adults may not show this thickening. T. delicatulum’s spire only bears 2.5 whorls, and it is quite long. The last whorl is cylindrical, but more straight-sided than in its sister taxon T. terebellum.

So, there you have it. If you didn’t know much about marine snails, hopefully you now know a little bit more than you did. One of the lessons out of this paper, I think, is that revisions and reviews are necessary to keep things in perspective. Whether you are a splitter or a lumper when it comes to taxonomic theory, it is always good to go back to the beginning and review the original author’s intentions. In some cases, looking a little different might not mean a new species. In other cases, this may be the opposite. Revisions give us new perspectives and allow us to learn more about the organisms that make our world so beautiful.

You can read more about my research in my publications, listed on my blog. You can also find me on ResearchGate, the James Cook University website and Twitter.

A little bit backwards … and what’s to come ahead?

Okay, so now you know all about my students. How about a little more about myself?

Since the start of 2016 and the present time, I have published 6 papers, and I have one currently under review:

Fig. 1. African striped mouse Rhabdomys dilectus chakae. Photo: P. Stanley; http://bit.ly/2oasJGo

•  Two are taxonomic papers. One describes a new species of Vasticardium from Queensland, while the other looks at commercial impetus of taxonomic inflation.
• Three are rodent papers. The first looks at how pre- and post-natal dietary protein influences cognition andbehaviour in African striped mice Rhabdomys dilectus chakae (Fig. 1), the second shows that inbred whistling rats Parotomys littledalei (Fig. 2) prefer to outbreed when they can, and the third shows that ice rat Otomys sloggetti robertsi (Fig. 3) colonies persist or fail as a unit, smaller colonies are likely to fail and that the persistence of colonies was positively predicted by foraging and negatively predicted by basking.

  

  Fig. 2. Littledale's whistling rat Parotomys littledalei. Photo: C. Paterson Jones; http://bit.ly/2niCWfy

  
  

• One is a review paper. Using a theoretical framework, we explore how we can estimate a species’ resilience and vulnerability to drought.
• One paper is currently under review. This paper has been submitted to the journal Mammalian Species, and includes a taxonomic description and life history characteristics of the fawn-footed mosaic-tailed rat Melomys cervinipes (Fig. 4). Watch this space!

Fig. 3. African ice rat Otomys sloggetti robertsi. Photo: P. Venter; http://bit.ly/2ojAqaI

I have developed more of an interest in animal personality and emotion over the last few years, particularly as fawn-footed mosaic-tailed rats come from extremely complex rainforest environments, which could have significant effects on their behaviour and cognition. I am also interested in exploring olfactory discrimination in more detail in this species, largely because we have little understanding of this. 

With the aid of my students, my work on fawn-footed mosaic-tailed rats has shown that at least one population has a behavioural syndrome that can be plotted along the bold-shy axis. We have also found some evidence of decoupling of personality traits along the calm-anxious and bold-shy axes. We’ve tested hormone concentrations, and correlated them with behaviours, but interestingly, physiological attributes only really become correlated in stressful situations. This was something that I predicted based on my honours student's, Emma Delarue, work.

Fig. 4. Fawn-footed mosaic-tailed rat. Photo: T. Rymer

Together with a colleague, Dr David Wilson from the Australian Institute for Tropical Health and Medicine, we are investigating fawn-footed mosaic-tailed rats response to odour cues from mygalomorph spiders. Preliminary results, which we presented at the Australasian Mammal Society conference in Alice Springs, Northern Territory, in 2016 suggest that they can discriminate cues, but not quite in the manner predicted. This is quite exciting for us, as this is the first study to test this in this species. We are currently gathering more data and a larger sample size to support our findings.

My masters student, Kelsey Paulling, is taking the next step with olfactory discrimination studies, using cues from reptiles. Hopefully, we can extend the data set to explore a range of possibilities, but, as the project is early stages at the moment, we are still ironing out methods. We have run a single test, using Pirate, one of the lab favourites, who is quite a charismatic and charming little mouse. Given Pirate’s bold personality, it was hardly surprising that he attempted to eat the sample. Hopefully, we’ll have some more definitive results in the next 6 months.

Because I'm a little rodent-minded, in my next blog, I'll introduce you to the first of the rodent species that captured my research interest (and my heart). You can read more about my research on rodents in my publications, listed on my blog. You can also find me on ResearchGate or the James Cook University website.