Varanus cumingi samarensis, Koch, André, Gaulke, Maren & Böhme, Wolfgang, 2010

Koch, André, Gaulke, Maren & Böhme, Wolfgang, 2010, Unravelling the underestimated diversity of Philippine water monitor lizards (Squamata: Varanus salvator complex), with the description of two new species and a new subspecies, Zootaxa 2446, pp. 1-54 : 19-23

publication ID

https://doi.org/ 10.5281/zenodo.195067

DOI

https://doi.org/10.5281/zenodo.6204334

persistent identifier

https://treatment.plazi.org/id/03E6336C-0021-0741-FF12-FCD805E9C2A7

treatment provided by

Plazi

scientific name

Varanus cumingi samarensis
status

ssp. nov.

Varanus cumingi samarensis ssp. nov.

Figures 9–14 View FIGURE 9 View FIGURE 10 View FIGURE 11 View FIGURE 12 View FIGURE 13 View FIGURE 14

Holotype. ZFMK 64713 ( Figs. 9–12 View FIGURE 9 View FIGURE 10 View FIGURE 11 View FIGURE 12 ), a subadult male, San Augustin near Gandara, Samar Island, Philippines, collected by M. Gaulke 1989.

Paratype. ZFMK 64712 ( Fig. 13 View FIGURE 13 ), an adult female, Tiomonan near Gandara, Samar Island, Philippines, collected by M. Gaulke 1989.

Other material. See appendix.

Diagnosis. A subspecies of V. c u m i n g i clearly distinguished from the nominotypic form by the following combination of characters: (1) A distinctive dorsal colour pattern of five to eight transverse rows of large yellow ocelli, spots, or markings on a black ground colour; (2) predominantly black dorsal side of the head with a varying extent of more-or-less symmetrical yellow markings; (3) black temporal streak sometimes bordered below by a bright stripe; and (4) no bright medio-dorsal stripe on neck and back. (5) Nostrils’ position on average about two and half times closer to the tip of the snout than to the eye (index 2 = 2.00– 3.29, mean = 2.41).

For details about scalation features and colour pattern of the remaining Philippine members of the V. salvator complex we refer to Tables 3 View TABLE 3 and 5 View TABLE 5 .

Description of holotype. A subadult male, the hemipenes are everted. The habitus is slender. Total length 901 mm (SVL = 343 mm, TaL = 558 mm, index 1 = 1.63), head length 65 mm, head width 35 mm, head height 20 mm. The nostrils are much closer to the tip of the snout than to the eye (index 2 = 2.40). The tympanum is oval-shaped. The tail is largely compressed laterally.

Scalation: The body scales are heterogeneous, 135 scales around midbody and 98 scales around the neck anterior to the gular fold. The scales of the head are irregularly pentagonal or hexagonal, 50 scales from rictus to rictus across the head. The scales around the eye are granulous. 61 (29 right/ 32 left) supralabials, plus one rostral; four enlarged supraoculars above each eye. The scale covering the pineal organ are likewise enlarged, star-shaped. The scales of the nape are smooth, oval, and larger than dorsals, in 29 transverse dorsal scale rows from a line connecting the hind margins of the ear openings to opposite of gular fold, and in 89 transverse rows from gular fold to the insertion of the hind legs. The limbs are covered with smooth, oval scales. The caudal scales are rectangular, above slightly keeled, below with prominent keels, twice as large as dorsally, 97 scales around the base of the tail, 50 after approximately one third of the tail length. The two median rows of dorsal tail scales form a double crest starting after the base of the tail. The gular scales are smooth, oval, 76 from tip of snout to gular fold increasing in size towards the gular fold. The ventrals of the belly are rectangular, arranged in 82 regular transverse rows between the gular fold and the insertion of the hind limbs. Anterior to the cloaca, two glandular areas of four to five scales each are located.

Colour pattern (in preservative). The dorsal side is black with five transverse rows of yellow-creamcoloured ocelli or markings between the fore and hind limbs ( Fig. 9 View FIGURE 9 ). The interspace between two distinct transverse rows is divided by a faded bright transverse line. The tail is striped with black and cream on the dorsal side. The eleven bright blocks increase in size towards the tip of the tail, and are separated by a thin dark line only on the first half of the tail length. The hind limbs are black spotted with single bright scales, the forelimbs are brighter because most scales are only marginally dark and have a bright centre. Digits with bright crossbands of one to two scale rows, first scale after each claw entirely brightly coloured. The neck is black with few bright markings. The head is dark between the eyes with only few bright scales. The snout is cream-coloured marked with four indistinctive dark crossbands. The tongue is bluish-grey only above, underside and first half are flesh-coloured ( Fig. 11 View FIGURE 11 ). The lateral side of the head is bright with a broad black temporal streak extending from the eye to the upper side of the tympanum. Ventrally cream-coloured, belly with fourteen partly interrupted dark crossbands between the fore and the hind limbs, further extending on the chest ( Fig. 10 View FIGURE 10 ). Throat and chin are bright without dark markings. Proximad, the tail shows indistinct longitudinal black ocelli changing to an alternating pattern of bright and black bars towards the end.

Genital morphology: The left and right hemipenes of the male holotype are fully everted ( Fig. 12 View FIGURE 12 ). The organs are about 40 mm long and sturdy passing into two asymmetrically shaped lobes. Both organs are fleshcoloured, only the truncus being strongly dark pigmented at its basal smooth paryphasman-free parts. The sulcus spermaticus is basally oblique, mesially running straight to the apex, where it ends laterally behind both hemibacula on the strongly asymmetrically shaped apical platform. The sulcus is largely open from the pedicel toward the apex. The hemibacula are cartilaginous, only weakly mineralized, and covered by tissue. They protrude from the apical platform which is strongly centre-emarginated at the asulcal side, mesially enormously enlarged, prolonged towards the truncus and markedly projecting to a lobe towards the sulcal side. The hemibacula are concavely bent towards the sulcus. The smaller, outer hemibaculum exhibits a welldeveloped emargination at its terminal ending. The paryphasman rows (‘frills’) are strongly developed and asymmetrically arranged. They are distally divided by a large median emargination on the asulcal side. On the upper truncus, the paryphasman rows are interrupted by the enlarged and truncal stretching apical platform. Only the proximal asulcal paryphasman rows, which narrow basally, are continuous and enter the sulcus spermaticus. Fourteen paryphasman rows are discernable from the proximal asulcal truncus to the smaller, outer hemibaculum. The lower truncus and pedicel are unornamented.

Variation. For a summary of main morphometrics and scalation features of V. c. s a m a re n s i s ssp. nov. we refer to Table 3 View TABLE 3 . The dorsal colour pattern of adult specimens consisting of distinct bright ocelli and/or spots may fuse and build more-or-less continuous bright crossbands on the back ( Tab. 5 View TABLE 5 ). There is a tendency towards additional, but usually indistinct transverse rows of smaller spots between the main rows but these may lack some specimens leaving the interspaces unicoloured black ( Fig. 13 View FIGURE 13 ). The amount and extent of bright markings on the head may vary considerably between different specimens. A bright temporal streak below the black stripe between eye and tympanum is sometimes not well defined. On the ventral side, the amount and extent of dark markings varies between specimens. Nine to fifteen more-or-less distinctive dark bars or crossbands have been counted.

No juvenile voucher specimens of V. c. s a m a re n s i s ssp. nov. were available to document a possible ontogenetic colour change in this taxon. However, from a photograph of a juvenile from Samar it can be assumed, that in contrast to the nominotypic subspecies the extent of colour change in V. c. s a m a re n s i s ssp. nov. is much less developed. Instead, the dorsal colour pattern seems to become more distinctive and rich in contrast with age.

Etymology. The subspecific epithet samarensis refers to the type locality Samar Islands, Philippines. We propose ‘Samar water monitor’ as its common name.

Distribution. V. cumingi samarensis ssp. nov. inhabits the islands of Samar, Leyte, and Bohol. At present, no statement can be made about the taxonomic affiliation of the island populations of Dinagat and Siargao located between Samar/Leyte and northern Mindanao. Furthermore, Gaulke (1991, 1994) noted a tendency towards a dark coloured phenotype in V. cumingi from Basilan but this small island is located only about 30 km off the west coast of Mindanao and belongs to the Mindanao subregion of Greater Mindanao. In the absence of material from Basilan, this island population should stay incertae sedis until new data are available.

Biology. No natural history data about this subspecies of V. c u m i n g i are available, other than that it inhabits lowland areas such as mangrove swamps and other coastal areas, riparian habitats, fishponds and rice fields ( Horn & Gaulke 2004; M. Gaulke unpubl. observ.). It is unclear whether it also occurs in higher altitudes and forests. No specimen could be sighted during a five-day stay in a forested mountain region on Bohol (Gaulke in Luxmoore & Groombridge 1989).

Conservation status. During a survey on Bohol Island in 1985, the population density of V. c. s a m a re n s i s ssp. nov. (then regarded as subspecies of V. s a l v a t o r) was considered relatively high in mangrove swamps and cultivated lowland areas (Gaulke in Luxmoore & Groombridge 1989), even though hunting and trapping for commercial purposes (skin trade) and subsistence hunting was active. Nevertheless, interviews with people involved in the skin trade suggested a decrease of the monitor lizard populations. One informant, who could easily trap 12–15 monitor lizards per week some years prior to the interview, could only trap 4–5 lizards during the time of the interview. No population data from the other distribution areas of V. c. s a m a re n s i s ssp. nov. are available, and no follow up investigation has taken place on Bohol. It can be assumed that the complete ban of the skin trade in 1994 has had a positive effect on the population status.

ZFMK

Zoologisches Forschungsmuseum Alexander Koenig

Kingdom

Animalia

Phylum

Chordata

Class

Reptilia

Order

Squamata

Family

Varanidae

Genus

Varanus