Eulipotyphla.

Presentation on theme: "Eulipotyphla."— Presentation transcript:

1 Eulipotyphla

2 “INSECTIVORA” “Taxonomic wastebasket” for very small, relatively unspecialized, insectivorous eutherians Dentition is tribosphenic or slightly modified [Fig. 14-9] Polyphyletic: Once included elephant shrews, tree shrews, More recently included tenrecs and golden moles

3 “Insectivora” as of 1990 small to medium sized, pentadactyl, plantigrade, long pointed snouts, sharp teeth pinnae and eyes usually small to absent

4 “Insectivora” simplified hindgut lacking a caecum an annular tympanic bone [absence of auditory bullae] smooth cerebrum

5 Monophyletic Insectivora now restricted to
Eulipotyphla: ("truly fat and blind“) 4 families, 442 species

6 Soricidae Distribution
Holarctic, Neotropical (to northern Colombia), Ethiopian, Oriental, Sulawesi and nearby islands.

7 Family SORICIDAE – some Texas shrews
Cryptotis parva Least shrew 4-8 g Notiosorex crawfordi Crawford's gray shrew

8 Soricidae characteristics
largest family of “insectivores” (26 genera, 376 species) constitute about 60+% of individuals in community composition studies when pitfalls are used rather than Sherman or other live traps.

9 2.5g (smallest living mammal) to 180 g
Characteristics 2.5g (smallest living mammal) to 180 g The pygmy shrew (Sorex minutus) weighs between 1.2 and 2.7 grams. high metabolic rate (must eat almost constantly) Rudimentary echolocation in Sorex and Blarina to locate prey

10 Characteristics saliva toxic in some
Blarina (short-tail shrews), the largest North American shrew (30 g), lower incisors have deep grooves produces neurotoxin (used to subdue mice, frogs, fish) and hemotoxin bites mice on neck and at base of skull; stores paralyzed arthropods. Causes pain and swelling in humans

11 11. Caravanning in shrews In crocidurines and some species of Sorex, females move their young in chains [Fig ]. This behavior is associated with disturbance of the nest and may be used to encourage the young to explore their environment.

12 Family Solenodontidae
Neotropical (Greater Antilles - Hispaniola and Cuba) 1 genus, 2 species large size, up to 600 g

13 Solenodontidae Feed primarily on invertebrates high frequency clicking for echolocation elongate, flexible, shrew-like snout for locating food neurotoxic saliva injected with grooved lower incisor

14 Solenodon threatened by rats, mongoose, dogs, cats and land clearing

15 Will I ever find anyone to
love me for something other than my dashing good looks?

16 Talpidae Moles 17 genera, 39 species Holarctic, Oriental Scalopus aquaticus the eastern mole occurs in South Texas.

17 Most are fossorial Feed on subterranean invertebrates
Family TALPIDAE Most are fossorial Feed on subterranean invertebrates Aerate the soil

18 Fossorial (Digging) Adaptations
Convergent evolution in all faunal regions Moles, gophers, ground squirrels, etc. (Fig. 12.4) Digging elements: teeth, feet, claws, head, snout. Reduced to absent eyes and pinnae.

19 Modifications of the forelimb and pectoral girdle in Talpids
forefoot usually broad, paddle-shaped, adapted for digging; digits point sideways; palms face backward; elbows point up [fig ]

20 More Modifications: Figure 14-13
Keeled sternum Long scapula Manus with falciform bone [‘sixth digit’] Blocky skull complete zygomatic arch

21 Mole Humerus and Ulna Humerus Blocky
Double articulation (with scapula and clavicle) [fig ] Ulna Long olecrenon

22 Levers • In-force (Fi): applied • Out-force (Fo): derived resistance
Out-lever arm L o Fo Out-force (force derived) (Power) In-lever arm L i pivot Fi In-force (force applied) Berta • In-force (Fi): applied • Out-force (Fo): derived resistance • In-lever (Li) vs out-lever (Lo )

23 Force vs. Velocity Vo = ViLo/Li Fo = FiLi/Lo Velocity (speed) • Force
Increase Vi= move muscle closer to joint Increase Lo = lengthen limb segment • Force Fo = FiLi/Lo Increase Fi= move muscle further from joint Decrease Lo = shorten limb segment Berta

24 Condylura [star-nosed mole]
semiaquatic, feeds on aquatic invertebrates Eimer's organs touch receptors on snout [Fig ] 11 pairs (22) of tentacles with 25,000 touch receptors more than a thousand tiny, dome-shaped cover each of the tentacles of the star-nosed mole ww.amnh.org/naturalhistory/ features/0600_feature2.html

25

26 Family Erinaceidae Hedgehogs [figs ] and Moon rats [Fig. 14.5] 10 genera, 24 species Ethiopian, Palearctic, Oriental

27 Family Erinaceidae Most with spiny (barbless) pelage, roll into ball for defense The Southeast Asian moon rats (gymnures) lack spines; when threatened, produce a foul smell. estivate in response to low food availability

28 Hedgehog characters 2 omnivorous: diet consists of invertebrates, small vertebrates, eggs, fruit. low cusps (unlike shrews or moles): used in crushing and grinding first lower incisors are well developed, but not as large as in shrews

29 end

30 end

31 Talpidae zygomatic arch complete

32 Condylura [star-nosed mole]
semiaquatic, feeds on aquatic invertebrates has 22 tentacles with 25,000 touch receptors [Fig. 8-23]

33 Family ERINACEIDAE