Fossil lungfish “brains” in eLife

Our latest article “Morphometric analysis of lungfish endocasts elucidates early dipnoan palaeoneurological evolution” was published yesterday in eLife.

In the way that many projects tend to go, the work for this article is several years in the making. I developed the seed of the idea during my time at Uppsala University (Sweden), and have been collaborating closely with Dr Tom Challands (University of Edinburgh) for several years to bring it to fruition. Together, Tom and I pooled our lungfish endocrania to more than double the number of those with “endocasts” known.

A cranial endocast is the internal space within the skull where the brain sits. As only the hard, bony parts of animals tend to fossilise we rely on the shape of these spaces to make inferences about the (now long gone) brain within.

Using synchrotron and micro-CT scanning technology, we were able to scan six new lungfish fossils to create virtual models of their endocasts. The fossils need to be exceptionally-preserved in 3D to be able to conduct these analyses. The fossils came from different sites from around the world (Australia, USA, Russia and Germany), but all hailed from the lungfish “heyday” of the Devonian Period (359-419 million years ago).

By combining these six new fossil models with all of the other lungfish endocasts known were were able to compile a dataset of 12 taxa which we then measured. The skulls of Devonian lungfish are highly variable in shape, and so we predicted that different endocast (brain) regions would undergo elongation as the external skulls changed shape.

Figure 12 from the eLife paper showing 10 fossil lungfish endocasts.

Along comes our heroic collaborator, Prof. Richard Cloutier (UQAR), who then had the unenviable task of making sense of our messy measurements and conducting some impressive morphometric analyses (a way of quantifying shape) despite our dataset having several missing variables (something not usually accommodated well in many morphometric analyses). We used several methods, including Bayesian Principal Component Analyses (BPCA) and PCA for incomplete data (InDaPCA) to untangle how the shapes of the endocasts differed from one another.

Figure 10 from the eLife paper showing a BPCA plot.

Our findings showed that contrary to our hypothesis where we thought different brain regions would tend to elongate within long skulls, most of the elongation (regardless of skull shape) tended to happen in the olfactory (sense of smell) region. We consider that sense of smell has remained an important sense throughout lungfish evolution.

We also uncovered some interesting things happening within the labyrinths (inner ears). The shape of inner ears can give a lot of information about an animal related to its sense of hearing, but also how it moves (locomotion). More investigation needs to be done but this may point to differing sensory requirements as lungfish evolved from deep sea animals to those living closer to shorelines in freshwater environments.

Ultimately we are continuing to learn more about brain evolution in this most fascinating group, the lungfish, which can in turn aid our interpretation of other groups -including our earliest fishy ancestors as they took the leap from water to land. Big thanks are due to all co-authors Tom Challands, Richard Cloutier, Laurent Houle, Per Ahlberg, Shaun Collin, John Long, as well as the editorial and reviewing team at eLife. If you would like to know more then I encourage you to read the article directly from eLife. All scan data is freely available for download from MorphoSource or Dryad.


I’m not sure that I have much wisdom to impart as I’m only writing this as a very new “parent in palaeo”. My son is just 9 months old and I’m imminently returning to work following maternity leave. It has been, as everyone says, a life-changing time and I have (mostly) enjoyed my days at home with the little one.

Before going on maternity leave I expressed some concerns about how being a mother in palaeontology/science/academia might potentially impact my career trajectory. I knew I worked in a male-dominated field, but it never felt more apparent than when I became pregnant. I wanted to seek advice from colleagues who had navigated the same journey as me, but it was difficult to find people in the same boat. I could see plenty of “parents in palaeo”, but looking for mothers (in the traditional, biological sense) was a harder task. Where are they all?

Alice at ~8 months pregnant (2021)

Unfortunately the career stage when most people become parents is during the vulnerable EMCR (Early – Mid Career Researcher) years when the majority of researchers are still navigating short-term, insecure contracts. It is no surprise then that it is during the EMCR stage we see the greatest effects of the “leaky pipeline”. (And relatedly, the numbers of women progressing from junior to senior levels suffers from what I’ll call the dreaded “scissor graph disappearing act”). I have no doubt that any time away from work compounds differences in output in our very competitive funding landscape and can therefore influence potential future success. The recent mothers I could see in STEM (in Australia particularly) were few and far between, and most of them continued to juggle insecure work.

Furthermore, years of insecure work throughout one’s late 20s and 30s can influence the decision about when to start a family. This was certainly the case for me, I had hoped for some job security prior to becoming a mother, but in the end I felt like I couldn’t wait much longer. I had my first child at age 37 and I don’t know if we will have any more. I do consider that if I had had secure work earlier in my career I might have started child-bearing younger and potentially had more children. In this way, a choice to pursue a career in science can directly impact one’s fertility.

Alice at home with baby Edvin

Similarly, academia often requires workers to relocate to new cities, new countries, new continents, taking people away from their traditional support networks such as extended families. This may influence when, and in what capacity, a parent might return to work after the birth or adoption of a child. Our families are based in Melbourne and Sweden respectively which renders our “village” pretty distant when we might otherwise call upon their help.  

Many people told me that I would “feel differently” about work once I became a mother (I note that no one ever said this to my partner, Niels). In some ways I think I was lucky that my work is a passion of mine, and being able to remain connected was a positive for me. Being a full time parent at home with a baby can be isolating and relentless in the day-to-day, and being able to check in occasionally with students and colleagues gave my brain a welcome escape from nappies, tantrums and breastfeeding. However, there were also times when I felt overwhelmed and frustrated to not be able to contribute as I would have liked, either due to the lack of time or headspace (usually both). Science is a highly collaborative pursuit, and the cycles of grant deadlines, student projects, and research papers doesn’t take a pause just because you do.

Alice with Edvin (6 months)

I’m lucky to have good support from my supervisor, colleagues and university so I feel positive about my immediate future. The long-term effects of choosing to have a family remain to be seen but I’m hopeful that our government and institutions can better accommodate working parents in the years to come.

I lived and worked in Scandinavia for a few years early in my career and saw how their more generous parental leave policies, with time allocated to both parents, and highly subsidized/universal childcare supported families and careers. I believe that Australia can do a lot better in this respect to improve equality at home and in the workplace. It is time for fathers and other non-birthing parents to take more time out of their careers to care for children too.

However, far from “changing priorities” and “feeling differently” about my career, I absolutely relish the idea of returning to work. I hope that by writing this piece I am increasing the visibility of at least one mother in STEM who is doing her best to (hopefully!) thrive as a “parent in palaeontology”.