Palæos:		Unit 460: Insectivora
The Vertebrates		100 Insectivora

Insectivora

Basal Insectivores & Golden Moles 

EUTHERIA
|--Insectivora
|  |--Chrysochloroidea
|  `--+--Micropternodontidae
|     `--+--Erinaceomorpha 
|        `--Soricomorpha
|           |--Tenrecoidea
|           `--+--Solenodontidae
|              `--+--Talpoidea
|                 `--Soricoidea
|                    |--Apternodontidae
|                    `--Soricidae  
|                       |--Crocidurinae
|                       `--Soricinae
`--+--+--ANAGALIDA 
   |  `--ARCHONTA
   `--+--FERAE
      `--UNGULATOMORPHA    

Taxa on This Page

1. Chrysochloroidea
2. Insectivora
3. Micropternodontidae X

Insectivora: (= Lipotyphla): Batodon, shrews, moles, hedgehogs, tenrecs. etc. 

Range: from the Late Cretaceous [N99]. 

Phylogeny: Epitheria:: ((Anagalida + Archonta) + (Ferae + Ungulatomorpha)) + *: Chrysochloroidea + (Micropternodontidae + (Erinaceomorpha + Soricomorpha)). 

Characters: Skull low and triangular [N99]; rostrum long and narrow [N99]; rostrum mobile [MN93]; maxilla widely expanded [$C88]; maxilla with substantial orbital wing extending into the middle of the orbit [MN93] [5] [A+02$?]; maxilla broadly contacting frontal in facial region [MN93]; lacrimal facial wing absent [$C88] or much reduced [MN93]; orbits fairly small & many fossorial forms effectively blind [V+00]; unique skull pattern from small orbit & large nasal capsules [$C88]; infraorbital canal generally short [MN93]; no postorbital bar [N99]; jugal reduced or absent [$C88] [MN93] (not synapomorphic) [N99] [V+00]; zygomatic arch usually incomplete [$C88] [N99] [V+00]; post-glenoid foramen for external jugular vein present [$C88]; occipital condyle, "ventral eminence" with sigmoid anterior border [MN93]; pinnae usually small or absent [N99]; mastoid large, ossified and incorporates tympanohyal [MN93]; large pyriform fenestra between otic capsule and basisphenoid [$C88]; tympanic annular [V+00]; auditory bulla frequently absent [C88] [V+00]; entotympanic frequently absent [V+00]; tympanic cavity often covered by processes from adjoining bones [V+00]; petrotympanic fissure present [MN93]; petrosal with distinct crest on medial promontorium [MN93]; alisphenoid surrounds fenestra ovalis [V+00]; bony dorsum sellae absent [$C88]; alisphenoid canal present [A+01$?]; large olfactory lobes mostly interorbital [V+00]; orbitosphenoid anterior to braincase (!?) [$C88] [V+00]; orbitosphenoid large [MN93]; brain small & cerebral hemispheres do not expand back over cerebellum [C88] [N99]; cerebrum smooth [C88] [N99] [V+00]; palatine reduced [$C88]; deciduous teeth shed early & rarely functional [N99]; all teeth rooted [N99]; dental formula typically 3/3, 1/1, 4/4, 3-4/3-4 [N99]; teeth with sharp cusps [V+00]; incisors large and specialized [V+00]; I1 larger than other anterior teeth [A+02$?]; canines reduced [V+00]; molars often zalambdodont or dilambdodont; limbs unspecialized and never saltatorial [V+00]; stance plantigrade, with 5/5 digits [C88] [N99]; clavicle present (except in the tenrec Potamogale) [N99]; digits I&V not opposable [C88] [N99]; pubic symphysis reduced (?) [$C88] [MN93$] [A+02$?] [4]; tibia with lateral flange (obturator ridge) joining lesser & greater trochanters [A+02$?]; tibia & fibula frequently fused distally [N99]; lack of differentiated hindgut, with cecum absent, large intestine absent, and short intestinal tract [C88] [MN93$] [V+00] [3]; testes internal [C88] [N99]; some groups with cloaca [N99] [V+00]; hemochorial placenta [MN93]; pelage of short, close-set fur, with fur not polymorphic, but may include spines [N99]; pelage with guard hairs only; high metabolic rate; nocturnal (except some shrews) [N99]; territorial, but little social structure. 

Note: [1] were it not for the Insectivora, the higher mammals would fall on a rather neat rodent - primate spectrum plus the ungulates. This group, along with perhaps the Carnivora, are what are what reduce mammalian taxonomy to total chaos. [2] The study by [A+02] did not include Chrysochloroidea.  Hence, the synapomorphies of Insectivora may apply to a more restrictive group.  Accordingly, they are all labeled as questionable.  [3] Unfortunately, as recognized by [MN93], this type of adaptation is also found in, e.g., insectivorous bats and pangolins.  [4] although this adaptation is found in all fossorial mammals, the same adaptation is found in all Insectivora, whether fossorial or not.  In non-fossorial species the symphysis is secondarily re-created by juxtaposed pre-acetabular surfaces.  Further, the usual symphysis exists embryonically and is lost, or replaced by the unique pre-acetabular contact [MN93].  [5] a possible synapomorphy, according to [MN93].  A problem is posed by the Chrysochloroidea, who have a rather unique orbital mosaic, and a possible reversal in the tenrec Potamogale.  However, these may be further derived states.  

Image: Upper Right: Erinaceus from the Mammalian Crania Picture Archive of the Department of Anatomy, Tokyo University School of Medicine.  Left & Lower Right: the Chrysochloroid (golden mole) Amblysomus hottentotus modified from [MN93].

Links: The Shrew (ist's) Site; Insectivora; IUCN/SSC - ITSES: Insectivore Specialist Group; Order INSECTIVORA; Order Insectivora; Mammalia: Insectivora; Entrez-PubMed; Entrez-PubMed; Order Insectivora; Insectivora; APUS.RU | Speesok Veedov | Mlekopeeta ... (Russian); Google Directory - Science > Biology > Flora and Fauna > Animalia ...; Mammalogy Image Archives- Insectivora; Order Insectivora- EnchantedLearning.com; Insectivores - Order Insectivora; Insectivora; ???? (Chinese & English); Bibliography of Insectivora; ordo Insectivora; Order Insectivora- Solenodons; Untitled; Main Page.  

References: Asher et al. (2002) [A+02]; Carroll (1988) [C88]; MacPhee & Novacek (1993) [MN93]; Nowak (1999) [N99]; Vaughan et al. (2000) [V+00].  ATW030720.

Chrysochloroidea: (golden moles) Amblysomus, Chlorotalpa, Chrysochloris, Cryptochloris, Eremitalpa, Proamblysomus.   

Range: from the Miocene, always restricted to Sub-Saharan Africa [N99] [V+00].

Phylogeny: Insectivora: (Micropternodontidae + (Erinaceomorpha + Soricomorpha)) + *.

Characters: head + body 8-24 cm [N99]; skull strongly conical, not flattened, with broad braincase [N99] [V+00]; nasals (?) & premaxillae form narrow, elongate snout, expanding distally into 2 processes for nose pad [N99]; rostrum covered by large leathery pad [N99] [V+00]; nostrils covered by flap on underside of snout [N99]; skull conical, broad at braincase & not constricted at orbits; eyes vestigial & totally covered by skin [N99] [V+00]; zygomatic arches formed by elongations of maxillae [MN93$] [V+00]; temporomandibular joint located posterodorsal to external ear [MN93$]; tabulars in occipital area [V+00$]; small ears hidden by fur; pinnae absent [V+00]; malleus greatly enlarged [V+00]; bulla formed from tympanic [V+00]; braincase not constricted between orbits [N99]; orbitosphenoid small [MN93]; dental formula 3/3, 1/1, 3/3, 2-3/2-3 [N99] [V+00]; diphyodont, with adult teeth emerging relatively late [V+00]; teeth slightly separated [N99]; I1 enlarged [V+00] (compare [N99]: all? incisors enlarged); 2 lateral incisors, canine & 1st premolars caniniform [N99]; P/p 2-3 molariform, narrow & wedge-shaped, with bladelike medial half [N99]; molars zalambdodont [C88] [A+02]; molars with 2 lateral cusps & 1 medial cusp, enamel ridge on both sides of medial cusp; molars high-crowned, with lower crowns twice as high as uppers [N99]; hyoid articulates with dentary [MN93$]; have short tails, invisible within fur [N99]; anterior chest wall deeply recessed to provide more room for arm muscle [N99] [V+00]; forearms & claws short & powerful [V+00]; forelimbs not rotated as in moles, retaining palm-down orientation [V+00]; distal forelimb with a third element or flexor bone, probably an ossified flexor tendon (see image) [V+00]; digits 4/5 [N99]; strong reduction in number of phalanges [MN93$]; manus V absent; huge claw on manus III & sometimes II [N99]; tibia & fibula fused distally [N99]; pes with 5 webbed, sharply clawed digits & naked sole [N99]; both sexes with single urogenital opening (cloaca) [N99]; pelage with distinctive iridescent sheen, thick, with a dense, wooly underfur [N99]; nosepad used extensively in digging (unlike true moles) [N99]; found in sandy areas, plains & forests [N99]; may be torpid in colder months [N99]. 

Note: [1] in molecular analyses, Chrysochloroidea usually group with the tenrecs in the Afrotheria. [2] The orientation of the arms is consistent with a unique digging style, in which scraping with forelimbs alternates with pushing dirt with the extremely strong snout, braced on the forelimbs.  [3] tend to live in dry soils or sands, with temporary tunnel systems, or simply using soil as a medium with out actual tunnel building.

Image: Skull of Chrysochloris asiaticus from the UMass Mammalogy Database.  

Links: Chrysochloroidea (Mikko's Phylogeny); 食虫目 (Chinese: brief discussion of diversity); Chrysochloridae Family (ADW: nice succinct description); Afrotherian systematics; mammsrch.phtml-family=Chrysochloridae (U. Mass. Mammalogy database); Molecular evidence for multiple origins of Insectivora and for a ... (Afrotheria); Untitled (lecture notes).  

References: Asher et al. (2002) [A+02]; Carroll (1988) [C88]; MacPhee & Novacek (1993) [MN93]; Nowak (1999) [N99]; Vaughan et al. (2000) [V+00].  ATW030711.

Micropternodontidae: Carnilestes, Micropternodus

Range: Early Paleocene to Early Miocene of China, Mongolia & North America

Phylogeny: Insectivora:: (Erinaceomorpha + Soricomorpha) + *.

Characters: infraorbital canal short [MN93]; maxillary root of zygomatic arch far back at M3 [A+01$?]; maxillary zygomatic rudiment reduced [A+01$?]; zygomatic arch incomplete, with jugal reduced or absent [A+01$?]; "no" zygomatic arch [MN93]; internal face of coronoid process deeply concave, but without pocket [A+01$?]; alveolar ridge on medial dentary running from m3 to condyle [A+01$?]; C1 with single root [A+01$?]; premolar series without diastema [A+01$?]; "semimolariform" P4 [MN93]; upper molars rectangular, with reduced stylar shelves; prominent metacone [A+02]; enlarged hypocones [MN93]; paraconids transversely oriented, crest-like; broad talonid basin [A+02]. 

Links: Micropternodontidae (Mikko's Phylogeny); Untitled Document (Carnilestes abstract).  

References: Asher et al. (2002) [A+02]; MacPhee & Novacek (1993) [MN93]. ATW030731.

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