The Humerus of Cryptotis Colombiana and Its Bearing on the Species’ Phylogenetic Relationships (Soricomorpha: Soricidae)

Abstract

The Colombian small-eared shrew, Cryptotis colombiana Woodman and Timm, was described from the Colombian Andes in 1993. Its original allocation to the C. nigrescens group recently was questioned based on several cranial characters the species appeared to share with some members of the C. thomasi group. We review characteristics of the C. nigrescens and C. thomasi groups, and we describe the humerus of C. colombiana and the humerus and manus of C. medellinia. The morphology of the humerus joins the suite of characters that supports the hypotheses that C. colombiana is not a member of the C. thomasi group and that all remaining South American species form a cohesive, definable set that is probably monophyletic.

Skeletal morphology of the forefoot in shrews (Mammalia: Soricidae) of the genus Cryptotis, as revealed by digital X‐rays

“…2) reveal considerable interspecific variation among the forefeet of the eight taxa that we investigated. These images support previous reports Timm, 1999, 2000;Woodman et al, 2003) of qualitative differences in the dimensions of the metacarpals and phalanges among species of Cryptotis, and they provide both a greater diversity of taxa and larger sample sizes per taxon than were available previously. Most notable are changes in the relative proportions and shapes of the individual elements comprising the digits.…”

“…In addition, they construct runways and burrows, using their forefeet for digging and pushing excavated soil aside (Whitaker, 1974). External variation in the forefoot among species of Cryptotis was revealed to be underlain by considerable osteological variation, and skeletal morphology of the manus provided characters that are potentially useful for understanding phylogenetic and ecological relationships Timm, 1999, 2000;Woodman, 2002;Woodman et al, 2003).…”

A new species of small-eared shrew (Mammalia, Eulipotyphla,Cryptotis) from the Lacandona rain forest, Mexico

“…Mandible moderately long and coronoid process of mandible high; anterior border of the coronoid process of the mandible joins horizontal ramus at approximately a right angle; the articular condyle is broad and short; the inferior sigmoid notch is very shallow; m1 and m2 with well-developed and pigmented entoconids and hypoconids; and only a hypoconid in talonid of m3. Forefeet relatively small; foreclaws neither broadened nor elongated, similar in proportion to other members of the C. nigrescens and C. parvus species groups (Woodman et al 2003); the length of 3rd claw averages 1.8 mm (6 0.08); humerus considerably long (8.1-8.3 mm) and narrow, without elongated processes; teres tubercle located proximal to the pectoral process; medial epicondyle short for the genus.…”

A new species of small-eared shrew in the Cryptotis thomasi species group from Costa Rica (Mammalia: Eulipotyphla: Soricidae)

“…Family Soricidae G. Fischer, 1814 Genus Cryptotis Pomel, 1848 C. thomasi group Choate, 1970 Members of the C. thomasi group are typically medium-to large-bodied (as measured by HB) species of Cryptotis with long skulls; reduced protoconal basin of M 1 relative to hypoconal basin; proportionally low to medium-height coronoid process, the anterior border of which joins horizontal ramus of the mandible at a relatively low angle; proportionally long and low P 3 ; unenlarged to slightly enlarged fore feet; elongate, but narrow fore claws; relatively straight humerus that, although large overall, is relatively shorter and more robust compared with humeri typical of members of the C. parvus and C. nigrescens groups (Woodman et al 2003).…”