The bambis, part 2: diminutive deer of the Americas
...continued from https://www.inaturalist.org/journal/milewski/53647-the-bambis-part-1-introduction-to-the-category-of-diminutive-ruminants#
In my Post of June 25, 2021, I introduced the term 'bambi' for those species and subspecies of ruminants with adult female body mass less than 15 kg.
Why have so many hoofed, cud-chewing lineages around the world evolved back down to the size of a terrier (see https://k9weightchallenge.com/dog-weight-loss-resources/dog-breed-weight-chart/), while retaining the anatomy of large deer and bovids?
The question of bambis in the Americas is of particular interest because this supercontinent is extraordinarily rich in lagomorphs and large rodents, which would seem the more suited to herbivorous niches at body masses of 6 to 15 kg.
Consider South America in particular. This continent combines an extreme faunal radiation of rodents (see https://en.wikipedia.org/wiki/Caviomorpha), extinction of most of its hoofed mammals about ten thousand years ago, and a complete lack of wild bovids even in the Pleistocene.
And consider that antlers, which virtually define deer, seem hardly worth shedding and regrowing repeatedly in the form of the short spikes likely in cervid bambis.
In this context, who would have been surprised to find that bambis are absent from South America?
And yet the reality is that more than a third of the wild species of deer on this continent are bambis.
This makes South America the richest continent for bambis as a percentage of the ruminant fauna, possibly even if camelids and the extinct deer of the late Pleistocene are included.
How can it be explained that the bambis have proliferated on the same continent as the large herbivorous rodents?
The bambi species and subspecies belong to two genera, as follows.
Mazama bricenii https://www.elimpulso.com/2020/07/19/datoimp-el-venado-matacan-es-endemico-de-venezuela/ and https://www.zoochat.com/community/media/parque-jaime-duque-2012.190741/ and https://www.zoochat.com/community/media/parque-jaime-duque-2012.190738/ and https://en.wikipedia.org/wiki/M%C3%A9rida_brocket and http://animal.memozee.com/view.php?tid=3&did=27990 and https://www.researchgate.net/figure/Male-of-Mazama-bricenii-from-Jaime-Duque-Zoological-Park-Colombia-courtesy_fig1_237471171 and https://www.zoochat.com/community/media/parque-jaime-duque-2012.190742/ and https://www.zootierliste.de/en/index.php?klasse=1&ordnung=121&familie=12109&art=50902279 and https://alchetron.com/Merida-brocket
Mazama chunyi https://www.inaturalist.org/observations/37793109 and http://animal.memozee.com/view.php?tid=3&did=27984
Mazama nana https://www.researchgate.net/publication/263300782_Brazilian_dwarf_brocket_deer_Mazama_nana_Hensel_1872 and http://portugal.inaturalist.org/taxa/42178-Mazama-nana and https://www.inaturalist.org/observations/11439535 and http://www.faunaparaguay.com/Mazama%20nana%20agatha%20boveda%20itaipu%20zoo.jpg
Mazama nemorivaga permira (restricted to one marine island in the Islas de Las Perlas archipelago) https://repository.si.edu/bitstream/handle/10088/32885/Buckley%20et%20al.%202017%20(separata).pdf?isAllowed=y&sequence=1
possibly Mazama nemorivaga in a disjunct population on the coastal mainland in eastern Brazil https://www.inaturalist.org/observations/51323572 and https://link.springer.com/article/10.1007/s10344-020-1367-2 and https://repository.si.edu/bitstream/handle/10088/32885/Buckley%20et%20al.%202017%20(separata).pdf?isAllowed=y&sequence=1
Mazama rufina https://www.researchgate.net/publication/237471132_DWARFT_RED_BROCKET_Mazama_rufina_Pucheran_1951/link/00463531a60ad130a3000000/download and https://www.inaturalist.org/observations/87609833 and https://www.inaturalist.org/observations/51233653 and https://www.inaturalist.org/observations/66792140
Mazama possibly an additional, unnamed species of bambi: https://web.archive.org/web/20040825142207/http://www.amazonconservation.org/home/News%20-%20dwarf%20deer.them.
Pudu mephistophiles https://en.wikipedia.org/wiki/Pud%C3%BA#/media/File:Pudu_mephistolephis.png and https://fundaciongaloplazalasso.org/en/english-pudu-rescue-kind-of/ and https://synapsid-taxonomy.tumblr.com/post/633754501583618049/pudu-mephistopheles-de-winton-1896
Pudu puda https://www.flickr.com/photos/jono-dashper/49804121392 and https://www.zooborns.com/zooborns/pudu/ and https://www.biolib.cz/en/image/id364360/ and https://www.sciencephoto.com/media/129599/view/pudu-pudu-mephistophiles-
Five of six species (putting aside the subspecies of Mazama nemorivaga) live along sections of the Andean chain of mountains; the sixth lives in southern Brazil, northernmost Argentina and easternmost Paraguay.
This suggests that a way to view the South American bambis is as 'insular miniatures' along the same lines as mammals on marine islands. Hoofed mammals confined to islands tend to become relatively small and short-legged because these situations have limited resources and unreliable climates but relative freedom from predation.
This seems particularly to explain the two species of Pudu, which are proportionately the shortest-legged of bambis worldwide, and have small, forward-facing eyes. Is Pudu not comparable with Myotragus balearicus (https://en.wikipedia.org/wiki/Myotragus) of western Mediterranean islands, an extreme example of insular evolution in a ruminant?
Any explanation comparing the Cordillera to an archipelago would not apply to Mazama nana, which lives at low altitudes. However, this is the largest of the South American bambis and the ecological counterpart for a like-size, lookalike bovid in southeastern Africa at similar latitudes and altitudes.
Please compare Mazama nana https://www.inaturalist.org/observations/34848637 and https://www.inaturalist.org/observations/60988368 with Cephalophus natalensis https://www.alamy.com/stock-photo-red-duiker-in-south-africa-53558012.html and https://www.naturepl.com/stock-photo-red-duiker-cephalophus-natalensis-kwazulu-natal-isimangaliso-wetland-nature-image01606122.html. In the light of this evolutionary convergence, Mazama nana is not as unexpected as the other species.
to be continued in https://www.inaturalist.org/journal/milewski/55883-the-bambis-part-3-smallest-of-all-deer-vs-smallest-of-all-bovids#...
תגובות
Really cool diary and observations @milewski. Thanks for share!
@patrich Many thanks to you and I look forward to your comments on the various topics.
I had no idea how many micro deers occur in South America, a grouo which I am not familiar, however, I have always thought that the dense forests dominated by Chusquea and ferns of southern Chile are an evolutionary force that drives dwarfism, just look at the Darwin's fox and pudu, both dwarf.
Muy interesante! Humans are also smaller here xD
The following is relevant to the short-leggedness of Pudu: https://journalofbiogeographynews.org/2020/10/18/the-mystery-of-low-gear-locomotion/.
I was reading Eisenberg's 1989 book and he states that within Colombia, Mazama rufina is only in the eastern chain of the Andes (Cordillera Oriental), while Pudu mephistopheles is only in the Central Cordillera. Looking a the few iNat observations, it seems M. rufina is also in the Central Cordillera, since the photos show a very deep rusty red coat color and a black face. (it's hard for me to gauge height from the photos).
What do you think about this? Is iNat right and Eisenberg need an update, or are we mis-ID'ing Pudu's in Central Cordillera as Mazama rufina?
I live in Colombia and want to better understand my local fauna. Thanks!
@crawfordaj
Many thanks for your question.
I'm afraid that I cannot sort this out on the basis of the information available in the Web.
What we do know includes:
1) Pudu mephistophiles has yet to be recorded in Colombia, in iNaturalist
2) Pudu mephistophiles resembles Mazama rufina closely enough that the two spp. have probably been confused to some extent in the past.
3) The species found in the Eastern Cordillera of Colombia is now called Mazama bricenii (https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0129113 and https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4488270/ and https://www.researchgate.net/publication/237471171_MERIDA_BROCKET_Mazama_bricenii_Thomas_1908).
4) Pudu mephistophiles is parapatric with Mazama chunyi in Peru.
5) There is possibly an additional, undescribed species of Pudu/Mazama in the Andes of Peru (https://www.researchgate.net/publication/342135583_Pudu_mephistophiles_Northern_Pudu_THE_IUCN_RED_LIST_OF_THREATENED_SPECIES)
I have scanned the various observations of M. rufina in Colombia, and I do not have the impression that they have been misidentified.
Given that the various spp. of bambis in the Andes can be differentiated by altitude and whether on the western slopes or the eastern, what is needed is more specimens from Colombia.
Until then, my best guess is that both Pudu mephistophiles and Mazama rufina occur in the Central Cordillera of Colombia, with the latter being more accessible and thus better-documented in iNaturalist. One cannot yet rule out the possibility that a fourth species of bambi awaits discovery within Colombia.
Wow, thanks for the explanation! Next time I meet a Colombian student of mammalogy, I'll mention these issues... maybe s/he would like to dig deeper some day. :-)
OH, it looks like 3 years ago iNat moved M. bricenii to M. rufina. https://www.inaturalist.org/taxon_changes?taxon_id=42173
Confusing for a frog person, like me. :-)
הוספת תגובה