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The Zoochat Photographic Guide to Rodents: part one

Discussion in 'Wildlife & Nature Conservation' started by Chlidonias, 12 Aug 2018 at 1:36 AM.

  1. Chlidonias

    Chlidonias Moderator Staff Member

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    Rodents dominate the Class Mammalia. About 42% of all mammal species are included within the Order Rodentia - there are twice as many rodent species as there are bat species. The general structure of the Order has remained fairly constant since the 1800s, the most major change being that the lagomorphs (rabbits, hares, and pikas) used to be included within the group until the start of the 1900s.

    Rodentia has been separated into three Suborders for almost 200 years - Myomorpha ("mouse-like"), Sciuromorpha ("squirrel-like"), and Hystricomorpha ("porcupine-like") - distinguished by the jaw structures. More recently, two further small Suborders have been separated from the Sciuromorpha - Anomaluromorpha (less than ten species) and Castorimorpha (about 100 species). These five Suborders are the currently-accepted divisions for most taxonomists today, although being taxonomy there are various other positions available for how to arrange the Order.

    As may be expected, the number of individual species in Rodentia has crept continuously upwards due to regular discoveries of unknown species and to genetics-based splitting (since 1980 about 600 new species have been added), but the number of Families has remained pretty steady, at between 30 and 35 - even if the exact placement of those Families within the Suborders hasn't always been agreed upon!

    I would encourage a reading of the Rodentia page on the website for Wilson and Reeder's Mammal Species of the World, which goes into much more detail about the taxonomy and history than I can give here: Mammal Species of the World - Browse: RODENTIA


    .......................................................................................


    I will be covering Rodentia across two threads. Part one (this thread) will include four of the five Suborders, with about 750 species in total. Part two will be just for the Myomorpha, with about 1500 species. (These numbers are entirely approximate until the threads are completed!)


    Part one:
    Suborder Sciuromorpha (c.330 spp)
    Suborder Anomaluromorpha (c.10 spp)
    Suborder Castorimorpha (c.100 spp)
    Suborder Hystricomorpha (c.300 spp)

    Part two:
    Suborder Myomorpha (c.1500 spp)


    There should be a fairly good representation of photographs for part one - at least most genera should have photographs even if there may be many individual species missing - but I suspect part two will be more like The Zoochat Photographic Guide to Bats where there will be long strings of listed species of rats and mice with only intermittent photos to break the monotony.


    .......................................................................................


    The presentation of Families as they will appear in these two threads are as follows. As earlier mentioned, the numbers of species given below are rounded approximations which will be corrected as the threads progress.


    Suborder SCIUROMORPHA (c.330 spp)
    Family Aplodontiidae - Sewellel or Mountain Beaver (1 sp)
    Family Sciuridae - Squirrels (c.300 spp)
    Family Gliridae - Dormice (c.30 spp)


    Suborder ANOMALUROMORPHA (c.10 spp)
    Family Anomaluridae - Anomalures or Scaly-tailed Squirrels (c.7 spp)
    Family Pedetidae - Springhares (1 or 2 spp)


    Suborder CASTORIMORPHA (c.100 spp)
    Family Castoridae - Beavers (2 spp)
    Family Geomyidae - Pocket Gophers (c.35 spp)
    Family Heteromyidae - Kangaroo Rats and Kangaroo Mice (c.60 spp)


    Suborder HYSTRICOMORPHA (c.300 spp)
    Family Diatomyidae / Laonastidae - Laotian Rock Rat (1 sp)
    Family Ctenodactylidae - Gundis (5 spp)
    Family Bathyergidae - Blesmols (c.20 spp)
    Family Hystricidae - Old World Porcupines (c.11 spp)
    Family Petromuridae - Dassie Rat (1 sp)
    Family Thryonomyidae - Cane Rats (2 spp)
    Family Erethizontidae - New World Porcupines (c.18 spp)
    Family Chinchillidae - Chinchillas and Viscachas (7 spp)
    Family Dinomyidae - Pacarana (1 sp)
    Family Caviidae - Cavies (c.20 spp)
    Family Dasyproctidae - Agoutis (c.13 spp)
    Family Cuniculidae - Pacas (3 spp)
    Family Ctenomyidae - Tuco-tucos (c.60 spp)
    Family Octodontidae - Octodonts (c.13 spp)
    Family Abrocomidae - Chinchilla Rats (c.10 spp)
    Family Echimyidae - Spiny Rats (c.90 spp)
    Family Myocastoridae - Coypu (1 sp)
    Family Capromyidae - Hutias (c.14 spp)


    Suborder MYOMORPHA (c.1500 spp)
    Family Dipodidae - Jerboas and Jumping Mice (c.50 spp)
    Family Platacanthomyidae - Spiny Dormice (2 spp)
    Family Spalacidae - Mole Rats and Bamboo Rats (c.40 spp)
    Family Calomyscidae - Mouse-like Hamsters (c.10 spp)
    Family Nesomyidae - Madagascan and African Rats and Mice (c.70 spp)
    Family Cricetidae - Hamsters, New World Rats and Mice, Voles, Lemmings, etc (c.600 spp)
    Family Muridae - "True" Mice and Rats, Gerbils, Spiny Mice, etc (c.700 spp)
     
    Last edited: 12 Aug 2018 at 3:23 AM
  2. TheWalrus

    TheWalrus Well-Known Member

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    I'm excited for this thread. Can't wait for the first post!
     
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  3. Okapipako

    Okapipako Well-Known Member

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    Oh lord. The big one. Godspeed, Chlidonias!
     
  4. Chlidonias

    Chlidonias Moderator Staff Member

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    In a year's time, when I finally finish this thread, I can sit back and say "Oh great, they've gone and named another forty rodents while I've been working..."
     
  5. WhistlingKite24

    WhistlingKite24 Active Member

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    Very ambitious! Can’t wait.:)
     
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  6. Chlidonias

    Chlidonias Moderator Staff Member

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    Suborder SCIUROMORPHA


    There are three Families within this Suborder, containing about 330 species in total: Aplodontiidae (the Sewellel or Mountain Beaver), Sciuridae (squirrels), and Gliridae (dormice).


    Gliridae has in the past been more commonly included within the Myomorpha (rats and mice), but it is now considered that the "myomorph" jaw structure of dormice is convergent and that they are actually sciuromorphs. However there are also suggestions that Gliridae is paraphyletic and that some members of the Family belong instead in Anomaluromorpha.


    The Suborders Anomaluromorpha (anomalures and springhares) and Castorimorpha (beavers, gophers, and kangaroo rats) have also been placed in Sciuromorpha in the past.
     
    Last edited: 12 Aug 2018 at 10:56 AM
  7. Chlidonias

    Chlidonias Moderator Staff Member

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    APLODONTIIDAE
    Aplodontids

    One living species


    This Family has an extensive fossil history from the Oligocene onwards, from across the entire Northern Hemisphere. Wikipedia lists 22 fossil genera in the Family. Today there is a sole living species, the Sewellel or Mountain Beaver, which has a limited distribution in the western USA. Despite the common name of the extant species, they are a sister group to squirrels and not closely related to beavers at all.


    Sewellel or Mountain Beaver Aplodontia rufa
    Seven subspecies: californica, humboldtiana, nigra, pacifica, phaea, rainieri, rufa


    There are no photos in the Zoochat galleries of live animals which have been taken by members. (That's a concise way of saying that there is an archive ZSL photo - Mountain Beaver or Sewellel (Aplodontia rufa) | ZooChat - and a couple of photos of an exhibit display which include a model Sewellel - Secrets of the Forest | ZooChat - but nothing which can be added to this thread).
     
  8. Chlidonias

    Chlidonias Moderator Staff Member

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    Family SCIURIDAE
    Squirrels


    About 300 species in 60 genera.


    The Family Sciuridae is divided into five subfamilies, as follows:


    Ratufinae (giant squirrels) - one genus: Ratufa

    Sciurillinae (Neotropical Pigmy Squirrel) - one genus: Sciurillus

    Sciurinae - twenty genera in two Tribes:

    Sciurini (tree squirrels) with five genera: Microsciurus, Rheithrosciurus, Sciurus, Syntheosciurus, Tamiasciurus

    Pteromyini (flying squirrels) with fifteen genera: Aeretes, Aeromys, Belomys, Biswamoyopterus, Eoglaucomys, Eupetaurus, Glaucomys, Hylopetes, Iomys, Petaurillus, Petaurista, Petinomys, Pteromys, Pteromyscus, Trogopterus

    Callosciurinae (Asian squirrels) - fourteen genera: Callosciurus, Dremomys, Exilisciurus, Funambulus, Glyphotes, Hyosciurus, Lariscus, Menetes, Nannosciurus, Prosciurillus, Rhinosciurus, Ribrisciurus, Sundasciurus, Tamiops

    Xerinae (ground squirrels) - twenty-four genera in three Tribes:

    Xerini with three genera: Atlantoxerus, Spermophilopsis, Xerus

    Protoxerini with six genera: Epixerus, Funisciurus, Heliosciurus, Myosciurus, Paraxerus, Protoxerus

    Marmotini with fifteen genera: Ammospermophilus, Callospermophilus, Cynomys, Eutamias, Ictidomys, Marmota, Neotamias, Notocitellus, Otospermophilus, Poliocitellus, Sciurotamias, Spermophilus, Tamias, Urocitellus, Xerospermophilus


    All the genera above are listed alphabetically under their Subfamily / Tribe, and they will be presented in the following posts in that same order.
     
    Last edited: 13 Aug 2018 at 10:29 AM
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  9. Chlidonias

    Chlidonias Moderator Staff Member

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    Ratufa
    Four species, all of which are represented in the Zoochat galleries.

    Ratufa is the sole genus in the subfamily Ratufinae.


    Cream-coloured Giant Squirrel Ratufa affinis
    Nine subspecies: affinis, bancana, baramensis, bunguranensis, cothurnata, ephippium, hypoleucos, insignis, polia

    The common name above is the most widely-used but I prefer to call them Variable Giant Squirrels because, while the subspecies in the mainland areas of southeast Asia are always solidly-coloured, on Borneo they come in multi-colour patterns and hence "Cream-coloured" is not at all appropriate.


    Photo by @devilfish at Lok Kawi Wildlife Park, Sabah (north Bornean subspecies baramensis - the northern part of this subspecies' range is split as sandakanensis by various authors, in which case the animal pictured here is sandakanensis)

    [​IMG]


    Black or Bicoloured Giant Squirrel Ratufa bicolor
    Eleven subspecies (possibly a species complex): angusticeps, bicolor, condorensis, felli, gigantea, hainana, leucogenys, melanopepla, palliata, phaeopepla, smithi


    Some of the named subspecies have discreet ranges (e.g. bicolor on Java and Bali, condorensis on Vietnam's Con Dao islands, felli in a small area of northern Myanmar, hainana on Hainan Island, and palliata on Sumatra), but for the others it is difficult working out where subspecies are supposed to be distributed. For example, Squirrels of the World by Thorington et al gives exactly the same distribution for angusticeps, leucogenys, melanopepla and phaeopepla, namely "Myanmar and Thailand south through peninsular Malaysia and the Natuna Islands (Indonesia)", and says that these subspecies are virtually indistinguishable from one another. There are a number of good photos in the Zoochat galleries of Black Giant Squirrels from Malaysia and Thailand but, with little available for me to say what's what, I have used only one of them (from Malaysia) simply as a comparison for the photos of known subspecies (bicolor, condorensis, gigantea).


    Photo by @Tomek at Wroclaw Zoo, Poland (Javan subspecies bicolor, showing the distinctive colouration in comparison to other subspecies)

    [​IMG]


    Photo by @Maguari at Saigon Zoo, Vietnam (Con Dao subspecies condorensis)

    [​IMG]


    Photo by @Chlidonias in the wild, Vietnam ("northern" subspecies gigantea)

    [​IMG]


    Photo by @Chlidonias at Melaka Zoo, Malaysia (one of the "southern" subspecies, used here as comparison to the known subspecies photos above)

    [​IMG]


    Malabar or Indian Giant Squirrel Ratufa indica
    Four subspecies: centralis, dealbata, indica, maxima


    Photo by @Chlidonias in the wild, India (subspecies indica)

    [​IMG]


    Photo by @Chlidonias in the wild, India (subspecies maxima)

    [​IMG]


    Grizzled or Sri Lankan Giant Squirrel Ratufa macroura
    Three subspecies: dandolena, macroura, melanochra


    Photo by @Goura at Leipzig Zoo, Germany (Sri Lankan Dry Zone subspecies dandolena)

    [​IMG]


    Photo by @Chlidonias in the wild, India (this isolated Indian population is treated as being of the same subspecies - dandolena - as is found in the Sri Lankan Dry Zone)

    [​IMG]


    Photo by @Chlidonias in the wild, Sri Lanka (Wet Zone subspecies melanochra)

    [​IMG]
     
    Last edited: 12 Aug 2018 at 12:15 PM
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  10. Chlidonias

    Chlidonias Moderator Staff Member

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    Sciurillus
    One species. This is the sole species in the subfamily Sciurillinae.


    Neotropical Pigmy Squirrel Sciurillus pusillus
    Three subspecies recognised - glaucinus, kuhlii, pusillus - although this could be a species complex.


    There are no photos of this species in the Zoochat galleries.
     
    Last edited: 12 Aug 2018 at 12:14 PM
  11. TeaLovingDave

    TeaLovingDave Moderator Staff Member

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    A very nice species, and one which I fear will soon be eligible for my "Species We Have Lost" thread given the fact that in the last decade all but one of the seven holders of the taxon have lost the species, and the final holder has not successfully bred their animals which are now quite old.
     
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  12. TZDugong

    TZDugong Well-Known Member

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    This is shaping up to be a long and interesting thread. Keep up the good work!
     
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