Leeway Corucia Research Center (LCRC)
Blenheim, S.C. 29516 U.S.A.
Abstract
Detailed measurements and observations differentiating the two subspecies of Corucia zebrata, Corucia zebrata zebrata and Corucia zebrata alfredschmidti, are described including new material not previously documented.
Key words: Corucia, Sclera, Parietal, Prefrontal, Rostral, Nasal
Introduction
Corucia zebrata zebrata (underlined) described and named (Gray, 1855) and Corucia zebrata alfredschmidti (underlined) described and named (Kohler, 1997) represent the two subspecies of Corucia zebrata (underlined) – the prehensile tailed monkey skink.
The common monkey skink (Corucia zebrata zebrata) hails from the larger islands of the Solomon archipelago southeast of Buka and Bougainville. This includes Choiseul, Guadalcanal, Isabel, Malaita, Nggla, New Georgia, Santa Ana, San Cristobal, Shortlands, and Ugi (Balsai,1995). The North Solomon monkey skink (Corucia zebrata alfredschmidti) hails from the North Solomons which are comprised of Bougainville and Buka (Kohler,1997).
Bougainville is by far the largest island in the archipelago and being on the northeast fringe of these islands, supported the establishment of peripheral isolates evolving into the subspecies alfredschmidti. This is supported by the sheer number and larger distribution of the subspecies zebrata in the southeastern islands. The core population of Corucia zebrata zebrata (underlined) appears to be from Quadalcanal (Balsai, 1995). The allopatric subspeciation of the Genus: Corucia reveals a larger size of Corucia zebrata alfredschmidti compared to Corucia zebrata zebrata. Indeed, a semi-Wallace line appears to exist between Bougainville and Choiseul. “There is an affinity along the lines of Bougainville – Choiseul, separated by the Bougainville strait, in which the faunal differences are relatively distinct (faunal differences 86%)” (Green/Slade,1968). Other animals show a size differential with the populations on Bougainville being generally larger than that on Choiseul. The monkey faced flying fox (Pteralopex anceps) on Bougainville is also larger (255-280 mm). On Choiseul, next to Bougainville, the population is smaller (160-275mm) (E. Bowen-Jones 1997).
The differences between Corucia zebrata zebrata and Corucia zebrata alfredschmidti are described here in detail which should aid in better appreciating the comparative differences between the two subspecies. As such, identification will achieve a faster result. However, once one has seen both Corucia zebrata zebrata and Corucia zebrata alfredschmidti, the visual difference in size and body coloration alone is readily apparent, even from a distance.
Snout/Vent Length (SVL) & Length Overall (LOA)
| Common monkey skink Corucia zebrata zebrata | North Solomon monkey skink Corucia zebrata alfredschmidti | |
| SVL | Average: Males = 250 mm Females = 270 mm Range: Males = 230 – 270 mm Females = 260 – 280 mm | Average: Males: = 320 mm Females: = 330 mm Range: Males: = 290 – 340 mmFemales: = 270 – 330 mm |
| LOA | Average: Males = 550 mm Females = 582.5 mm Range: Males: = 520 – 580 mm Females: = 560 – 605 mm | Average: Males: = 660 mm Females: = 670 mm Range: Males: = 630 – 680 mm Females: = 640 – 690 mm |
Number of individuals of equal proportions used in study: 96.
A noticable difference in size of neonates is also in evidence: (LOA)
Corucia zebrata zebrata averages about 11 1/2″ (Langerwerf, 2006, Schnirel, 2001)
Corucia zebrata alfredschmidti averages just under 15″ (Schnirel, 2004)
Czz / Cza neonate comparison:
Corucia zebrata zebrata LOA = 289 mm
Corucia zebrata alfredschmidti LOA = 370 mm
Note: Both subspecies of Corucia zebrata (underlined) reproduce by viviparous matrotrophy with the birth of a single very large neonate. Occasionally, twins are produced, there is one documented case of triplets (Langerwerf, 2003).
Weight (Average): Adult Neonate
Common monkey skink = 500 Grams 81 Grams
Corucia zebrata zebrata
North Solomon monkey skink = 845 Grams 173 Grams
Corucia zebrata alfredschmidti
Number of adult Corucia used in study : 96. , Number of neonate Corucia used in study : 39.
Source: LEEWAY CORUCIA RESEARCH CENTER (LCRC); Courtesy of POLYPHEMOS (2006)
Contributed to Biology-online on Aug 28, 2006
