It's another stunning Malagasy #dartfrog/#poisonfrog for today's #FrogOfTheDay, #42 Mantella cowani Boulenger, 1882! A highly threatened, actively conserved and managed frog from the highlands of central #Madagascar
#MadagascarFrogs
📸D.Edmonds/CalPhotos

This thread will cover only a tiny fraction of the work on Mantella cowanii because, being so charismatic and threatened, it has received quite a bit of attention.
#MadagascarFrogs
We start at the very beginning: the first specimens, two females, were collected by Reverend Deans Cowan in East Betsileo, Madagascar, and sent to London, where George Albert Boulenger described the species in 1882.
#MadagascarFrogs
Boulenger placed the species in his new genus, Mantella, along with ebenaui, betsileo, and madagascariensis. He recognised that the other Malagasy poison frogs were distinct from the Dendrobates of the Americas, although he did keep them in the Dendrobatidae.
#MadagascarFrogs
As more specimens were collected, it became clear that the species was highly variable. In 1978, Jean Guibé wrote with interest about this variability, describing a new subspecies, M. cowani nigricans—today a full species. #MadagascarFrogs
https://t.co/dwaHMbrYbj
Although Guibé was wrong about the affinities of those two species, it is true that there is astounding variability of colour in this (and other) Mantella species, and that they evidently hybridise with other species.
#MadagascarFrogs
📸B.Freiermuth/CalPhotos
Little was known about Mantella cowanii in the wild until the 1990s. By 1999, when Miguel Vences et al. published a revision of Mantella, it was known from a few different locations, but populations between it and M. baroni posed challenges to identification.
#MadagascarFrogs
These frogs occur in bizarre habitat in central Madagascar, often with wet, exposed rocks interspersed with low bushes.
📸Mantella cowanii Action Plan, 2021–2025 (on which more below)
The first (?) DNA-based phylogeny came out in 2002, confirming close affinity with M. baroni and M. nigricans, and showing that Malagasy poison frogs may have Müllerian mimicry generating repeated colour pattern evolution. https://t.co/4qqzbiiAev
#MadagascarFrogs
The hybridisation of M. cowanii with M. baroni received a lot of interest, in part because the species are generally morphologically and ecologically distinct.
https://t.co/VMFGZ7tP0Y
https://t.co/9uFZ7KBRzZ
International interest has always been strong in the beautiful #Mantella #frogs, so M. cowanii were targeted for the pet trade. Between 1988 and 2003, some 12,877 individuals were reportedly exported from Madagascar.
https://t.co/gJXip5xMTv
#MadagascarFrogs
In 2005, @CITES imposed a zero quota on M. cowanii, effectively banning export. For a species known from only a few locations in threatened habitat, and low fecundity (Tessa et al., see link), harvesting at these rates was unsustainable.
#MadagascarFrogs
https://t.co/SAON3F2VqF
Until 2014, Mantella cowanii was listed as Critically Endangered, but it was then downgraded to Endangered. Apparently the population declines seen until 2003 were halted by the cessation of trade. https://t.co/2rS29qFNQT
#MadagascarFrogs
Nevertheless, Mantella cowanii is heavily threatened. Representatives of @ASG_IUCN @Voakajy @amphibiansorg @chesterzoo and other organisations are actively involved in its conservation. A new action plan for 2021–2025 was just released.
#MadagascarFrogs
https://t.co/ozm89CMSSR
As I understand it, captive populations of Mantella cowanii are being maintained. So, if extirpated, it might be possible to reintroduce this frog, as long as habitat remains available. So there is hope for the 'harlequin' mantella!
#MadagascarFrogs

More from Science

1/ Automobiles and Intake Fraction. Since cars are back in the news I thought I would retweet this model result I offered in early April 2020. I focused only on 1 micron particles & accounted for windows completely closed & cracked slightly open.


2/ Related air exchange rates were based on experimental results in literature for mid-sized sedans. Particle deposition to indoor surfaces were accounted for, as the surface to volume ratio in a 3 m3 cab is large. An important outcome was the intake fraction (IF)

3/ Here, IF is the number of particles (or virions in collective particles) inhaled by a receptor DIVIDED BY the number or particles (or virions in collective particles) emitted by an infector.

4/ Integrated over the two hour drive (in this example) the IF for all windows closed & a receptor at rest is 0.08 (8% of what comes out of the infectors respiratory system ends up in the respiratory system of the receptor). 8%! That is a very high intake factor.

5/ With additional ventilation from cracking a window open drops the IF to 0.012 (1.2%) still relatively high. Can get lower by opening more windows.

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