Note: On some weeks, I get lazy with keeping up with the mountains of tables of contents and cite alerts. This was one of those weeks, so apologies if I missed any “big” papers.
These are papers that may be of general interest published this week, with commentary as necessary. No specific case studies, overly specialised research, or taxonomic papers. Papers ordered only by their appearance in my inbox. For PDFs, e-mail me, I get most of them. You can request an in-depth analysis of any paper and I’ll do it as I get the time.
Open-access papers, those that are free to read/download even without an academic connection, are tagged with [OA] for easy finding with your browser’s text search (Ctrl+F).
11 papers this time, 3 open access.
Index:
- Special Issues [3]
- Arthropods [2]
- Ecology [2]
- Palaeontology [4]
- Phylogenetics [1]
- Zoology [2]
Special Issues:
I was most interested in González-Castro et al. because of the focus on the Mediterranean, and Calviño-Cancela et al. for being a generally interesting scenario.
For those interested in biomechanics, some very cool papers here.
This is a special issue in the Journal of the History of Biology.
Arthropods:
My favourite factoid for further scaring people of cockroaches is to confirm to them that cockroaches are social animals. The human imagination plays wonderful tricks on them. If you too would like to be an asshole like me, read this paper to get some precise information on their sociality.
- Ventilation of the giant nests of Atta leaf-cutting ants: does underground circulating air enter the fungus chambers?
The architecture that ants are capable of is pretty remarksable, although you may be disappointed that they don’t manage to bring in fresh air several meters deep into the soil. Still, good try, and it does work well enough to allow fungal gardens to grow.
Ecology:
The metabolic theory of ecology, as outlined in the milestone Allen et al. (2002), is a purported causal explanation for biogeographic patterns in species diversity and richness, finding that there is a mathematical relationship between the kinetics of metabolism and temperature, thus explaining why species richness is higher in lower latitudes (high average temperature), or lower in higher altitudes (lower temperature). It’s an intriguing idea, and since 2002, analyses, metanalyses, and data compilations have found various amount of support for it, from none to full. This paper is the latest in this back-and-forth, with the main finding being that the mathematics of the current metabolic theory are too simplistic and need to be worked on some more to fit the data.
My new-found experience working with aquatic invertebrates in temporary lakes and ponds has given me an extreme appreciation for the resilience of these organisms and especially their eggs/cysts. They can survive seasons and even years in drought, and they can live for days in the digestive system of birds. This latter case is what this review paper is about. From personal, unpublished data from the two large salt lakes in Cyprus, I can confirm that waterbirds are indeed pretty important when it comes to dispersing aquatic animals.
Palaeontology:
Even if you’re not interested in palaeobotany, it’s pretty impressive just how much information can be extracted with modern techniques.
In any talk of the end-Permian mass extinction, the severity of the event will be stressed by the fact that ecosystems took a very long time to recover. While this is undoubtably true, this paper brings up another, unrelated factgor: the temperatures in the early Triassic, after the extinction, were abnormally high – high enough, apparently, to drive life out of the lower latitudes on land, and to suppress the growth of many of the typical aquatic organisms we see preserved in the fossil record. This brings up the question of to what degree the supposed slow recovery is a result of the mass extinction and to what degree is it of this climate change.
- Leehermania prorova, the Earliest Staphyliniform Beetle, from the Late Triassic of Virginia (Coleoptera: Staphylinidae).
The earliest anything deserves a mention, right? In this case, the earliest known staphyliniform and, more importantly, polyphagan beetle (although earlier beetles exist, their polyphagan affinities can be disputed). This particular one bears a resemblance to rove beetles.
Bias in the fossil record is one of my pet issues (see this post for example). What is said here can be applied to all groups.
Phylogenetics:
I have mixed feelings about this. On the one hand, it’s excellent for teaching the relationships of mammals (and other animals and organisms when the website gets updated) – I will be trying to use it in my own classroom projects. On the other hand, the fractal format has several limitations, the most important of which is the impossibility of including a time axis, which is extremely important to show phylogenies. As it is, it only shows relationships, albeit in a very intuitive way that I bet will appeal to school students and the lay public.
Zoology:
The neocortex is the mammalian brain region that handles the demanding cognitive and social tasks. This paper finds that the unique 6-layered neocortex of the mammals isn’t an entirely novel structure, but one that’s derived from an ancestral brain region from the amniotic ancestor, since the cell types homologous to those in the mammalian neocortex are also found in birds, just forming very different structures.
- The nervous system of Isodiametra pulchra (Acoela) with a discussion on the neuroanatomy of the Xenacoelomorpha and its evolutionary implications. [OA]
Xenacoelomorpha is a brand new genus, erected by Philippe et al. (2011) in order to unite the acoelomorphs and Xenoturbella, in accordance with their molecular phylogeny. It’s also supported by several morphological characteristics and the basal position of the acoels, so I personally find no major problem with this classification. This paper gives some insight into this arrangement from the nervous system of an acoel. There are some absolutely gorgeous pictures in here too. If you want to know more about acoels, check the thorough Achatz et al. (in press) [OA].
