*Palæos:*		Unit 470: Anagalida
*The* *Vertebrates*		100: Anagalida

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Anagalida

Abbreviated Cladogram

EUTHERIA
|--INSECTIVORA  
`--+--+--Anagalida
   |  |  |--Zalambdalestidae
   |  |  `--+--Macroscelidea  
   |  |     `--+--Anagaloidea
   |  |        |  |--Anagalidae
   |  |        |  `--Pseudictopidae
   |  |        `--Glires
   |  |           |--Lagomorpha
   |  |           `--RODENTIA
   |  `--ARCHONTA
   `--+--FERAE
      `--UNGULATOMORPHA

470.000 Overview
470.100 Anagalida
470.400 Anagaloidea & Glires
Cladogram
References

Zalambdalestidae, Anagaloidea and Fashion Statements

The zalambdalestids recently have acquired the status of indispensable accessories to a fashionable mammalian pedigree. They are included among the Anagalida, as close cousins to rabbits, rodents and elephant shrews. They are traditionally referred to the Insectivora, as proto-shrews; and they are frequently mentioned in the same breath with zhelestids as early ungulatomorphs. At the same time they are claimed by some very chic basal eutherian clans as asioryctotherians or even leptictidans. This is all a bit odd because no one seems to have paid any serious attention to the anagaloids, who are evidently close connections, since Malcolm McKenna's work in the 1960's and 1970's. See, e.g., McKenna (1963). Perhaps the Paleocene to Eocene anagaloids simply come too late to be of much interest. Otherwise, it is hard to ascribe this discrimination to anything but scientific fashion.

The zalambdalestids are attractive as rabbit or macroscelidan ancestors since they are clearly jumping animals, and had an elongated rostrum quite possibly supporting a proboscis similar to those of elephant shrews. Unfortunately zalambdalestids are both too early and too primitive to be near the direct line of descent. More likely, they simply illustrate a precocious development of some of the design possibilities inherent in the eutherian plan.

Descriptions

Anagalida:

Range: from the middle Cretaceous or Late Cretaceous

Phylogeny: Epitheria :::: Archonta + * : Zalambdalestidae + (Macroscelidea + (Anagaloidea + Glires)).

Image: a degu from Silke & Frank / Degus.

Links: Root Anagalida; Salles (English & French); Molecular Systematics; Classification Table; EEvvoolluuttiiee vvaann ddee PPrriimmaatteenn eenn ddee MM; Mammalian mitogenomic relationships and the root of the eutherian ...; Genera and species of Paleocene mammals - Part 2; Paleocene mammals of the world; Rabbits and Hares; Rodent Phylogeny and a Timescale for the Evolution of Glires- ... (a molecular study with reasonable results!); Synonyms of the Anagalida; Brief report; The interphotoreceptor retinoid binding protein gene in therian mammals; Usage Optimization of Unevenly Sampled Data through the ...; Molecular Systematics. ATW040118

Zalambdalestidae: Alymlestes, Barunlestes, Kulbeckia, Zalmbdalestes

Range: middle Cretaceous or Late Cretaceous of Mongolia and Central Asia

Phylogeny: Anagalida : (Macroscelidea + (Anagaloidea + Glires)) + *.

Characters: elongated snout largely due to growth of maxilla, but with some contribution from premaxilla [A+01]; maxilla extends posteriorly along choanae [K+00]; postglenoid process extends only along medial portion of glenoid glenoid fossa [L+01]; occipital plate inclined anteriorly from the condyles [K+00]; braincase more inflated and the "mesocranial region" (between palate & otic capsules) is shorter than in asioryctitherians, but longer than modern placentals [C88] [K+00]; promontorium flattened [K+01]; carotid foramen is medial (lateral in living mammals) [K+01]; basisphenoid with prominent pterygoid process [K+00]; cerebellum short & wide [C88]; presphenoid with prominent median process [K+00]; neocortex probably very small [C88]; dental formula variable, generally trending to reduced formula of Glires [A+01]; large, medial, procumbent and ever-growing ("open-rooted") lower incisors [A+01] [FK02]; incisors with enamel restricted to outer surface (or at least asymmetrically distributed on outer surface) and near the crowns [A+01]; I1 not enlarged [FK01]; i1 incisor oval in cross-section [FK01]; i1 roots extend to level of m1 (Barunlestes) [FK02]; i1 roots particularly thin-walled with large pulp cavity [FK02] i1 straight and procumbent, not curved upward as in Glires [FK02] axis with long spinous process [3] [K+00]; atlas intercentrum fused to neural arch [C88]; thoracic vertebrae with short spinous processes [K+00]; scapular spine present [C88]; no separate coracoid or interclavicle [C88]; tibia & fibula strongly fused [K+00]; astragalus with tibial trochlea well developed [K+00]; astragalus fully proximal to calcaneum [C88]; hind limbs and metatarsals very long [K+00]; strongly adapted for reliance on olfaction and hearing, probably nocturnal [K+00].

Note: [1] according to [FK02], it is not clear that the i1 of Zalambdalestidae is homologous with the i1 of Glires. [2] see image above for braincase features. [3] this process is just visible on the skeletal reconstruction. A similar structure is present in ricochetal rodents. It limits the mobility of the cervical vertebrae and stabilizes the neck for jumping [C88].

Links: Zalambdalestidae after McKenna & Bell, 1997 and Archibald, ...; MESOZOIC MAMMALS; Zalambdalestidae and K cimolestids, an internet ...; Barunlestes butleri; Dinosaur Gallery: Zalambdalestes; Basale Säugetiergruppen Evolution der Säugetiere (German); Lecture 11 -Insectivora.

References: Archibald et al. (2001) [A+01]; Carroll (1988) [C88]; Fostowicz-Frelik & Kielan-Jaworowska (2002) [FK02]; Kielan-Jaworowska et al. (2000) [K+00]. ATW021105.

Macroscelidea: elephant shrews: Elephantulus, Myohyrax, Nementchatherium, Rhynchocyon.

Range: fr upEc of Afr.

Phylogeny: Anagalida :: (Anagaloidea + Glires) + *.

Characters: 40- 600g & 10-30 cm body length; cranial: long, flexible, very sensitive snout [N91]; nostrils at end of snout [N91]; palate with 2-3 paired fenestrae; (see macroscelidea.jpg) large jugal; zygomatic arch complete & slight; orbit large; small postorbital processes; no postorbital bar; small olfactory lobe; pinnae large; auditory bulla complete, with entotympanic bone and contributions from several other elements; dental: high-crowned teeth (hypsodont) with dilambdodont molars; dental formula: 1-3/3, 1/1, 4/4, 2/2-3 [N91]; I1s widely spaced [N91]; incisors form straight, anteroposterior row; posterior incisors caniniform; upper canine is double-rooted & molar-like; P4 is largest cheek tooth; molars quadrate; molars dilambdodont [N91]; last molar (m3? M2?) reduced & vestigial; chew by grinding as rabbits; tail 8-25 cm [N91]; axial: tail with species-specific bristles [N91]; tail with sexually dimorphic scent-marking gland on underside [N91]; appendicular: limbs long and slim; digits 5/4-5 [N91]; ulna and radius closely appressed; hind limbs much longer than forelimbs [N91]; tibia & fibula fused; highly adapted for cursorial (saltatorial?) locomotion; cecum present; polyovulate, with up to 120 eggs per ovulation, but only 2 fertilized eggs implant; abdominal testes; other: carnivorous or insectivorous (from ground litter); live in plains or less commonly forest, rocky outcrops; generally monogamous; most are solitary or pair-bonded (1 species social) [N91]; territorial with scent marking and fixed trails, ritualized aggression displays; territories defended sex-specifically (males v. males etc.); gestation ~60 dy [N91]; young are precocial, with sexual maturity in 5-6 weeks [N91].

Links: Elephant Shrew Skull; EL-SHRWS; Order Macroscelidea/ Family Macroscelididae; Lecture 12 - Mac/Der/Scan.; Macroscelidea; Elephant Shrew - Elephantulus rufescens; septhreo.html; Rüsselspringer (German); JBC -- Graham et al. 271 (26): 15623; Macroscelidea after Tabuce, et al., 2001; Elephant Shrews - Order Macroscelidea; Macroscelidea; Comparative Mammalian Brain Collections: Macroscelidea; Tanzanian Mammal Key; Elephant-Shrews (important site, perhaps Best on the Web).