Biology 4429 Chapter 11 Slide1 Order Insectivora

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Biology 4429 Chapter 11
Slide1 Order Insectivora

  1. Placental mammals

  2. The ecologically dominant mammals of the Cenozoic

  3. 18 Orders (plus 4 extinct Orders), about 3,800 species

  4. Characteristics of Placental Mammals

    1. Chorioallantoic placenta (Fig. 9.11B, pp. 153-156)

    2. Primitive dental formula is

3/3-1/1-4/4-3/3 = 44


1 The Order Insectivora has been used as a scrapbasket for a variety of very small, relatively unspecialized, insectivorous eutherians with cheekteeth simple, tritubercular or quadritubercular.

2 Tree shrews, elephant shrews, and dermopterans have been placed in separate orders.

  1. Until recently, restricted to the Lipotyphla

A shrews, solenodons, moles, hedgehogs, tenrecs and golden moles.

Slide 4 Lipotyphla

A. Characters

1. Simplified hindgut lacking a caecum [Fig. 6.2]

2. small to medium sized
3. pentadactyl, plantigrade limbs
4. long pointed snouts
5. sharp teeth
6. pinnae and eyes are usually small to absent.
7. annular tympanic bone [absence of auditory bullae]
8. smooth cerebrum
Slide 5 Eulipotyphla

1 Insectivora is now restricted to the Eulipotyphla.

2 4 or 5 families, 390 species

3 shrews, moles, hedgehogs, solenodons, Nesophontes

4 Molecular evidence indicates golden moles and tenrecs belong in the Afrotheria, a taxonomic group that also includes elephants, sea cows, hyraxes, aardvarks, and elephant shrews.

5. A new order "Afrosoricida" comprises Chrysochloridae (golden moles) and Tenrecidae (tenrecs)

Slide 6 Family SORICIDAE

A. Shrews [fig. 11.11]

Slide 7 Soricidae Distribution

Holarctic, Ethiopian, Oriental, Neotropical (to northern Colombia)

Slide 8 Soricidae Charateristics

  1. Largest family in order (23 genera, 312 species).

  2. Constitute about 60% of individuals in community composition studies when pitfalls are used rather than Sherman or other live traps (!)

  3. 2.5g (smallest living mammal) to 180 g

  4. high metabolic rate (must eat almost constantly)

  5. Rudimentary echolocation in Sorex and Blarina to locate prey

Slide 9 Soricid characters, cont.

  1. Long slim snout, Small eyes, Ears usually visible

  2. No zygomatic arch (Fig. 11.12)

  3. I1, large hooked

  4. strongly procumbent lower incisors

Slide 10 Soricid characters, cont.

  1. saliva toxic in some (e.g. Blarina)

Slide 11 Caravanning in crocidurines

Slide 12 Blarina
Slide 13. The Desert Shrew, Notiosorex crawfordi, is common in South Texas
Slide 14 Sorex minutus


Slide 16. Solenodons [fig. 11.9]

  1. Neotropical (Greater Antilles: Hispaniola and Cuba, until recently in Puerto Rico)

  2. 1 genus, 2 species

  3. large size, up to 600 g

  4. Feed primarily on invertebrates

  5. high frequency clicking for echolocation

  6. elongate, flexible, shrew-like snout for locating food

  7. neurotoxic saliva injected with grooved lower incisor [Fig. 11.10]

Slide 17 Solenodon extinction threat

Slide 18 Family TALPIDAE

  1. moles [fig 11.4]

  2. Holarctic, Oriental.

  3. 17 genera, 42 species

  4. Scalopus aquaticus the eastern mole occurs in South Texas

Slide 19 Convergent evolution in fossorial mammals

  1. Taxa

A. Convergent evolution in all faunal regions [Fig. 11.8]

  1. Adaptations

    1. Blocky skull, Zygomatic arch complete

    1. Eyes minute, ears lack pinnae, etc.

    1. Modifications of the forelimb and shoulder girdle [Fig.11.4]

Slide 20 Modifications of the forelimb and pectoral girdle


Slide 21 Figure 11.4

Slide 22 Mole Humerus

Fig. 8.21

Slide 23 Levers



Slide 25 Talpid skull [Fig.8.20]

Slide 26. Touch receptors (Eimer’s organ) on snout [Figs. 6.4, 20.7]

Slide 27. Condylura, the star-nosed mole
Slide 28. Old World desmans feed on aquatic invertebrates and fish

Slide 29


Slide 30 hedgehogs [figs. 11.2, 11.3] and moon rats

  1. Ethiopian, Palearctic, Oriental

  1. genera, 21 species

  1. Most with spiny (barbless) pelage, roll into ball for defense.

  1. Moon rats (gymnures) lack spines; when threatened, produce a foul smell.

  1. can estivate

Slide 31. Skull and dental characteristics

  1. Omnivorous: diet consists of invertebrates, small vertebrates, eggs, fruit.

  1. Low cusps (unlike shrews or moles): used in crushing and grinding

  1. First lower incisors are well developed, but not as large as in shrews

Slide 32 Order AFROSORICIDA [Fig. 11.6]

Slide 33 Family TENRECIDAE

Slide 34 Tenrecidae

A. Ethiopian
B. Urogenital and anal opening terminating in a cloaca
C. Tenrecs [fig. 11.7A, B]

1. Adaptive radiation of 8 genera & 21 species from Madagascar

2. Many are hedgehog-like, can roll into ball with spines

Slide 35 Potamogale, the giant African water shrew [Fig. 11.7C]

    1. 2 genera and 3 species

    1. West-central Africa

3. Large size, up to 650 mm and 4 kg


Slide 37 Golden moles

1. Ethiopian

2. 7 genera, 18 species
3. Fossorial (p. 76)
4. Resemble marsupial moles and true moles
5. Adaptations of the forelimb for burrowing
6. Uses head and forefeet to burrow
Slide 38 Pictures of golden moles
Slide 39 Burrowing Behaviour
Slide 40 Order Macrosclelidea
elephant shrews

  1. Ethiopian, North Africa

  2. long (especially distally) hind limbs, can move bipedally

  3. snout long, slender, movable at base

  4. large eyes, long ears

  5. generally diurnal

  6. insectivorous

  7. mouse (50 g) to squirrel-sized (200)

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