AMPHIBIAWEB
Callulina shengena
family: Brevicipitidae
 
Species Description: Loader SP, Gower DJ, Ngalason W, Menegon M 2010 Three new species of Callulina (Amphibia: Anura: Brevicipitidae) highlight local endemism and conservation plight of Africa's Eastern Arc forests. Zool J Linn Soc 160: 496-514.

© 2010 Michele Menegon (1 of 1)
Conservation Status (definitions)
IUCN (Red List) Status
CITES
Other International Status None
National Status None
Regional Status None

Country distribution from AmphibiaWeb's database: Tanzania, United Republic of

 

View distribution map using BerkeleyMapper.

   

From the Encyclopedia of Life account:

Etymology

The species is named after the peak in the South Pare (Shengena) from where the type series was collected. The specific epithet is considered to be a noun in apposition.


Author: Loader, Simon
License: http://creativecommons.org/licenses/by-nc/3.0/

Summary

A large Callulina, snout-urostyle distance reaching 43.2 mm. Snout-tibia ratio 33-38%. Tympanum is absent. Toe and finger tips are truncate and not expanded. Subarticular tubercles of hands and feet are prominent. A coloured interocular band, usually darkened in preservative but pinkish/reddish in life, and a continuous enlarged glands on arms and legs are present.


Author: Loader, Simon
License: http://creativecommons.org/licenses/by-nc/3.0/

Distribution

Callulina shengena has been found only in montane forest dominated by the forest tree Ocotaea usambarensis at elevations between 1920 m and 2100 m. Based on current knowledge of the species’ distribution and evidence of forest dependancy, the estimated extent of occurrence of C. shengena is equal to or less than 35 km2, and the known area of occupancy is about 3 km2; these are respectively the area including the elevational distribution (1920 – 2100 m) of this species in the Chome forest reserve and the area included in the polygon obtained by linking the localities where the presence of the species was recorded. The species is common in the area in which it has been found, but it is confined to the montane forest zone where persistent and large scale logging of O. usambarensis occurs. Extensive areas of the forest appear to be heavily logged and considerable habitat damage is done during this process. The presence of one population at only a single, small location is compounded by an observed decline in area and quality of the habitat (Hall et al., 2009).


Author: Loader, Simon
License: http://creativecommons.org/licenses/by-nc/3.0/

Osteology

de Sá et al., (2004) and Loader et al., (2009) provided assessments of the internal morphology of the new Callulina species they described. These two studies utilised characters previously identified in Parker’s (1934) review of the morphological diversity in microhylids (brevicipitids were previously classified in Microhylidae). Largen & Drewes (1989) provided additional data in their description of the new brevicipitid genus Balebreviceps. Largen & Drewes (1989) and Parker’s (1934) studies provided important characters for differentiating primarily among breviciptid genera, less so among species (de Sa et al., 2004; Loader et al., 2009). For this study we investigated the skeletal morphology of all the new species, and provide brief summaries.

Characters common to all Callulina species: (1) Palate with denticulate ridge in front of pharynx, and anteriorly two weakly defined, broad arcuate smooth ridges. (2) Parasphenoid cultriform process broad based but narrower, almost wing-like structure tapering medially, the anterior end tapering only slightly. (3) Mentomeckelian – posteroventral processes smaller than those of Probreviceps; wedge-shaped as in Balebreviceps but with a more acute angle. (4) Procoracoids and clavicles present, well developed, straight, slightly curved distally at the joint between coracoid and scapulae. (5) Large omosternum. (6) double condylar articulation between the urostyle and the sacral vertebra. (7) Diplasiocoelous vertebrae.


Characters varying among Callulina species: Bony part of finger and toe tips expanded clearly beyond the width of the base of the terminal phalanx in C. kreffti, expanded marginally in C. stanleyi and C. kisiwamsitu, about same width of the base of the phalanx in C. dawida, C. laphami, and C. shengena.


Author: Loader, Simon
License: http://creativecommons.org/licenses/by-nc/3.0/

Morphology

Body robust and stout. Tips of fingers truncate, only very marginally expanded laterally (equivalent to width of distal subarticular tubercle), rounded edges, with lateral circummarginal grooves; first finger shortest, second and fourth equal, third longest. Inner metatarsal tubercle large, rounded and raised, separated by a middle palmar tubercle from an even larger, rounded, raised, outer metatarsal tubercle. Smaller tubercles present on palm. Subarticular tubercles at the base of each finger, large subarticular tubercles on third and fourth finger at the phalangeal joints. Third finger with two smaller tubercles between basal articular tubercle and subarticular tubercles. Truncate, slightly dorso-ventrally expanded toe tips without any lamellae on ventral surface; tips of toes not expanded laterally, with circummarginal grooves posterior to distal phalanx. First toe same length as second, third and fifth equal, fourth longest. Inner metatarsal tubercle large, rounded and raised, touching a smaller, rounded, raised, outer metatarsal tubercle. Smaller palmar tubercles present on base of foot. Subarticular tubercles at the base of each toe, large subarticular tubercles on third and fourth toe at the phalangeal joints. All tubercles on hands and feet bluish/grey against brown/grey background. Dorsal, lateral and ventral aspect of arms and legs with large, conspicuously coloured, continuous glands; on the arms continuous from the wrist to the elbow on dorsal and dorso-lateral surface; glands on the legs bifurcate, one part from knee joint to the tibiotarsal joint on the dorsal, lateral and ventral surface, the second part continuous from tibia to the tibiotarsal joint to the base of the foot on the dorsal, lateral, and ventral surfaces to the foot, the gland attenuating on a diagonal angle on the dorsal surface of the foot ending at the base of the fifth toe.


In life, dorsum dark brown with a pinkish/reddish interocular bar, connected to a larger continuous, roughly diamond shape pink/reddish area extending over the anterior part of the dorsum, paler brown on shoulders to elbows. Relatively smooth dorsal surface, only slightly granular, with larger glandular masses on lateral sides and posterior end around the thighs and urostyle region. Large glandular mass marked by slightly paler cream. Ventral paler yellow to cream-tan. Lateral sides darker brown/grey, mottled. Right hand side of mid ventrum with irregular grey patch, left hand side of mid ventrum shows a conspicuously marked vein, directed diagonally posteriorly and laterally spanning out from mid area. Edges of chin slightly greyish. Tympanic region greyish/brown. Door-like incision on both left and right surface of skin around tympanic region reveals underlying musculature and absence of any tympanum or vestigal elements. Weakly defined but darkly edged tympanic region. Loreal and canthal regions pale grey. Nostrils, snout tip, jaw angle slightly darker grey. Snout visible from ventral view.


Author: Loader, Simon
License: http://creativecommons.org/licenses/by-nc/3.0/

Diagnostic Description

C. shengena diffes from C. kreffti, C. kisiwamsitu, and C. stanleyi in lacking a tympanum, smooth, less granular skin, truncate finger and toe tips, and the presence of a bright colour in the ocular region. C. shengena and C. dawida are similar in overall appearance, both have an interocular colouration, but the latter has a tympanum, albeit sometimes obscured (Loader et al., 2009). Furthermore, C. laphami lacks the prominent arm/leg glands of C. shengena. The distinctiveness of C. shengena from all other Callulina is also supported by distribution and DNA sequence data.


Author: Loader, Simon
License: http://creativecommons.org/licenses/by-nc/3.0/

Habitat and Ecology

Loader et al. (2010) collected specimens in bucket pitfalls in the forest. Individuals found at night were perched on small understory branches, as well on bushes between 1 and 2.2 m above ground. One individual was sitting among the irregularities of the bark of a tree at over 2 m. One male and two females were found together at about 1.5 m high, sitting on small tree branches.


Author: Loader, Simon
License: http://creativecommons.org/licenses/by-nc/3.0/

Advertisement Call

No call was heard or recorded by Loader et al. (2010).


Author: Loader, Simon
License: http://creativecommons.org/licenses/by-nc/3.0/

Phylogenetics

To test the distinctiveness of Callulina species and infer their evolutionary relationships we constructed two alignments of sequence data for all six described species: (1) all Callulina individuals for which 12S and 16S were available (2) all individuals for which 12S, 16S and cytb were available. The two datasets comprised (1) 18 individuals with 762 unambiguously aligned characters, of which 533 were constant, 89 variable, and 140 informative under parsimony (only 1 gap present, alternative coding of this gap made no difference in resulting trees), and (2) 14 individuals with 1185 unambiguously aligned characters, of which 884 were constant, 98 variable, and 203 informative under parsimony. Phrynomantis was used as outgroup as in previous analyses, following Loader et al., (2009). Analysis of Alignments 1 and 2 yielded single most parsimonious (MP) trees of 422 and 870 steps, respectively, and the trees (not shown) are not notably different to those recovered in likelihood and Bayesian analyses. Maximum likelihood (ML) and Bayesian analyses were conducted with the GTR+I+G model. Both analyses supported the monophyly of Callulina, and rejected suboptimal topologies in most tests. For Alignment 1 both analyses demonstrate the genetic distinctiveness of the named species, with highly supported reciprocally monophyletic groupings recovered for each, and suboptimal topologies significantly different in MP tests (apart from C. stanleyi - see Figure 8a). The truncate finger/toe species (C. dawida, C. laphami, C. shengena) form a paraphyletic assemblage outside a clade of all expanded finger/toe species. The sister species grouping between C. shengena and C. laphami is weakly supported. The expanded finger/toe clade of C. kreffti, C. kisiwamsitu, and C. stanleyi is weakly supported, though the sister pair of the morphologically similar C. kisiwamsitu and C. stanleyi is strongly supported. Both analyses of Alignment 2 recover multiple individuals of each named species (where included) together in maximally supported clades and significantly different from suboptimal topologies. Different from Alignment 1, C. shengena is recovered as the sister to all other species instead of grouping with C. laphami, though this is weakly supported. Analyses of Alignment 2 (as with Alignment 1) recovered a truncate toed paraphyletic assemblage outside a clade of all expanded finger/toe species. Constrained topologies including a monophyletic North and South Pare radiation (C. stanleyi, C. lapami, C. shengena), or a monophyletic South Pare (C. stanleyi, C. shengena) radiation are both statistically significantly suboptimal for both alignments using MP and ML (p= <0.05). Pairwise distances show high values highlighting the genetic distinctiveness of all named Callulina species (>4.2%, mean of 8.4% among all species).


Author: Loader, Simon
License: http://creativecommons.org/licenses/by-nc/3.0/