Callulina stanleyi, Loader & Gower & Ngalason & Menegon, 2010

Loader, Simon P., Gower, David J., Ngalason, Wilirk & Menegon, Michele, 2010, Three new species of Callulina (Amphibia: Anura: Brevicipitidae) highlight local endemism and conservation plight of Africa’s Eastern Arc forests, Zoological Journal of the Linnean Society 160 (3), pp. 496-514 : 505-509

CALLULINA STANLEYI SP. NOV.

( FIGS 1 , 4 , 5C , 6–8 , TABLE 1, 2)

Holotype: BMNH 2000.207, adult (gravid) female, collected at Chome Forest Reserve , South Pare Mountains (04°09′60″S, 37°50′48″E) by MC on 18 April 1996. Found under a rotten log in forest. This specimen has been sequenced for 12S, 16S, and cyt b. Specimen in good condition, slightly desiccated in parts, with a cross-like midventral incision into the coelom.

Paratypes: Ten specimens: BMNH 2008.467 (male; sequenced for 12S and 16S) and 2008.468 (male; cleared and stained), formerly MTSN 7540 and 7543, respectively; FMNH 251381–251384, collected by WTS, SMG, and CM in a pitfall trap, 7 km south of Bombo (4°20′S, 38°00′E; 1100 m a.s.l.), Chome Forest Reserve, South Pare Mountains on 20–24 July 1993 ; MTSN 7541 (male), 7542 (female), 7544, and 7559 (female), collected at Chome Forest Reserve , South Pare Mountains (04°19′41.382″S, 37°59′44.262″E; c. 1230 m a.s.l.), by MM between 13 and 15 March 2008 .

Diagnosis: A medium- to large-sized robust Callulina . Snout–urostyle distance reaching 42.5 mm, snout: tibia ratio 0.33–0.39. Tympanum present but sometimes obscured by granular skin. Finger tips usually expanded, with the ratio between the width at first subarticular and the width at distal phalanx 0.8–1.0. Subarticular tubercles of hands and feet prominent.

Callulina stanleyi sp. nov. differs from C. kreffti in having a less expanded third finger (distal width at third terminal phalanx/distal width at subarticular tubercle> 0.75). Callulina stanleyi sp. nov. differs from C. dawida in having expanded finger and toe tips. Callulina stanleyi sp. nov. differs from C. laphami sp. nov. and C. shengena sp. nov. in the presence of a tympanum, and expanded toe and finger tips. Callulina stanleyi sp. nov. is morphologically very similar to C. kisiwamsitu , although the two species can be distinguished on the basis of DNA sequence, call, and distribution data. Additionally, the following morphometric characters (against SUL) differ significantly (P <0.05) in the two species, based on Student’s t -test analyses: ED, IOD, HW, ND, NLD, TD, snout length (as measured from lower lip to apex of anterior dorsal margin of snout), and outer metatarsal tubercle of the hand (as measured along its longest axis). Many of the head character differences between C. stanleyi sp. nov. and C. kisiwamsitu indicate the larger, more robust head of C. stanleyi sp. nov.

Description of holotype: Body robust. Tips of fingers expanded, distal width of terminal phalanx 0.85 of the width of distal subarticular tubercle. Tips of fingers expanded laterally, with circummarginal grooves posterior to distal phalanx. First finger shortest, second and fourth equal, third longest. Inner metatarsal tubercle rounded and raised, separated by a middle palmar tubercle from an even larger, rounded, raised, outer metatarsal tubercle. Slightly smaller palmar 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 smaller tubercles between basal articular tubercle and subarticular tubercles. Slightly dessicated but dorsoventrally expanded toe tips, with slightly folded but smooth ventral surfaces. Tips of toes slightly expanded laterally, with circummarginal grooves posterior to distal phalanx. Toe tips with smooth ventral surfaces. First toe same length as second, third and fifth equal, fourth longest. Inner metatarsal tubercle large, rounded, and raised, almost touching a similar sized, 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. Dorsum brown with scattered, darker brown–black symmetric vermiculations. Skin granular, with slightly larger glandular masses on lateral sides, and posterior end around the thighs and urostyle region. Large glandular mass slightly paler brown. Ventral surface paler brown, cream–tan. Tympanic region pale brown–cream. Dark edged tympanic ridge from posterior edge of eyelid to arm insertion. Incision around tympanic region on right side. Loreal and canthal regions dark brown. Snout visible from ventral view.

Measures of holotype (all measurements are given in mm): ED = 3.0; ETD = 1.2; HL = 12.1; HW = 11.8; IN = 1.8; IOD = 7.2; LF3 = 4.7; LT4 = 6.6 , NED = 2.2; NLD = 1.5; SUL = 42.5; TD = 1.3*; TL = 9.6; TSL = 10.8; WDF3 = 1.3; WDTF3 = 1.1. (* Difficult to discern, was dissected to clarify exact measurement.) Measures of male paratype (MTSN 7541) : ED = 4.6; ETD = 2.8; HL = 8.3; HW = 8.7; IN = 2.8; IOD = 4.4; LF3 = 3.6; LT4 = 4.7; NED = 3.1; NLD = 1.2; SUL = 24.6; TD = 1.7*; TL = 14.8; TSL = 6.9; WDF3 = 1.1; WDTF3 = 0.9. (* Difficult to discern, was dissected to clarify exact measurement.)

Morphological and colour variation: Morphological features of paratypes generally match the holotype. The proportion of TL to SUL is 0.33–0.39. The size and position of the tympana varies: TD / TL = 0.04– 0.06; ETD / TL = 0.04–0.07. The ratio of the widths of the third distal phalanx to the subarticular tubercle is 0.77–1.0; most specimens are in the range 0.77– 0.86. FMNH 251381 is a small (19.9 mm SUL) juvenile that is dessicated, with only marginally expanded finger tips (WDF3 = 0.6; WDTF3 = 0.6; ratio = 1), and FMNH 251384 is a small juvenile with expanded finger tips (WDF3 = 0.7; WDTF3 = 0.5; ratio = 0.71) .

The juveniles FMNH 251381–251384 resemble the holotype in colour, but show different degrees of dark mottling on the dorsum, with FMNH 251382 most strongly mottled and FMNH 251383 the least mottled. The tympanum is obscured by granular skin in MTSN 7541, 7543, and 7544.

Colour in life: Generally brown, with irregular darkbrown marbling. Warts on the lateral surfaces of body clearly white. Ventral surface cream with brown marbling on edges. Eyes orange to red ( Fig. 3C ).

Advertisement call: Males were only calling during the night, from low bushes and branches of small trees. The call is a fast series of between seven and nine trills ( Fig. 5 ), produced at a rate of approximately fve per second, with maximum energy at 1720 Hz. The quality of the few call recordings was not high enough to allow a detailed description of the train of pulses forming the trill. Pulse-group duration was about 25 ms, and intergroup duration was about 116 ms.

Natural history: The holotype was collected in a rotten log in the forest. The FMNH specimens were all collected in bucket pitfalls in the forest. Specimens were found on low bushes during the night, both in dense forest and along a forest road.

Distribution and threat: Callulina stanleyi sp. nov. was found only in submontane forest at elevations between 1200 and 1300 m. Based on current knowledge of the species’ distribution and evidence of dependency on the forest, the estimated extent of occurrence of C. stanleyi sp. nov. is less than or equal to 9.7 km 2: this is the area including an elevational distribution (1200–1600 m) of the submontane habitat in Chome. As with the two other newly described species, population density does not appear to be low, but C. stanleyi sp. nov. is confined to a small fragment of submontane forest existing along the eastern boundary of Chome forest reserve, which is bordered by extensive farmlands. The presence of one population at only a single, small location is compounded by an observed decline in the area and quality of the habitat ( Hall et al., 2009).

Etymology: This species is named after our colleague and good friend William T. Stanley of the Field Museum, Chicago. Bill has made numerous contributions to understanding the biological diversity of the Eastern Arc Mountains. He has also made several important field discoveries of amphibians (including those we describe from the South Pare), and we name this species in recognition of his excellent work.

Figures

Figure 1. Map of the Eastern Arc Mountains of Tanzania showing the distribution of Callulina. Inset map (bottom left) showing the distribution of South Pare species Callulina stanleyi sp. nov. (elevational range of 1200–1600 m), and Callulina shengena sp. nov. (elevational range of 1920–2100 m).

Figure 3. Dorsal, ventral, and laterial views, and ventral aspect, of hands and feet of the holotype of Callulina shengena sp. nov., MTSN 9285.

Figure 4. Dorsal, ventral, and laterial views, and ventral aspect, of hands and feet of the holotype of Callulina stanleyi sp. nov., BMNH 2000.207.

Figure 5. Colour in life of Callulina laphami sp. nov. (top left), Callulina shengena sp. nov. (bottom left and right), and Callulina stanleyi sp. nov. (top right).

Figure 6. Snout–urostyle length in Callulina, showing mean, minimum, and maximum values.