Varanus spinulosus

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Varanus spinulosus
Varanus spinulosus.JPG
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Family: Varanidae
Genus: Varanus
Subgenus: Solomonsaurus
Species:
V. spinulosus
Binomial name
Varanus spinulosus
Mertens, 1941
Synonyms [2]

Varanus indicus spinulosusMertens, 1941

Varanus spinulosus, the Solomon Island spiny monitor, Isabel monitor, [1] [2] or spiny-neck monitor, [3] is a species of monitor lizard. It is endemic to the Solomon Islands archipelago and is also known from Santa Isabel Island, San Jorge Island (Solomon Islands) and Bourgainville Island (Papua New Guinea). [1] [2]

Contents

Taxonomy

Varanus spinulosus was first described by Robert Mertens in 1941 from a singe male specimen, and named Varanus indicus spinulosus as a subspecies of the mangrove monitor. This species was known only by the holotype until 1989, when 5 female specimens were collected. In 1994, the taxon was elevated to specific status as Varanus spinulosus, [4] but remained a member of the subgenus Euprepriosaurus and the V. indicus species complex until it was declared incertae sedis in 2010, when it was concluded that the species likely represented a new subgenus due to its genital morphology. [5] In 2016, the monotypic subgenus Solomonsaurus was coined for this species based on its unique scale structure, the latter which is reflected by this taxon's specific epithet spinulosus, meaning "spiny". [6] A 2020 phylogenetic analysis suggests that this species dispersed to the Solomon Islands shortly after the genus Varanus formed 30 million years ago in the Oligocene, and is not particularly closely related to Euprepiosaurus, which diverged much later in the Late Miocene. [7]

Description

This species is in many respects similar to the mangrove monitors of the V. indicus species complex, but has a number of unique morphological characteristics, and is not particularly closely related to them. [7] It has a spiny scale texture as each of the small body scales are strongly keeled and conical in shape, which is a feature unique amongst all monitor lizards. It has 3-4 rows of bright yellow spots running across its back, and has relatively large eyes. [6] It also possesses a distinct and acute canthus, a feature that is generally uncommon among other monitor species. Spiny-necked monitors also generally retain an "extreme dark morph" coloring, a trait likely stemming from the geographic restriction of the species. Unlike most mangrove monitors, this species maintains a uniform black ventral surface, and does not have light facial coloring. They also possess enlarged colored scales, with a lack of distinct mandibular bar patterns prevalent in other Varanidae, something observed only in this species. This species also possesses a variant pink base tongue color, though a third of the anterodorsal portion could also share the same pigment. [8]

Habitat

This species generally resides in xeric (areas with higher rainfall during a selective period per year) and quasi-xeric environments. The selective environments for settling resulted in geographical restrictions to the Bismarck Archipelago and Solomon Island chains. [8]

Lifespan

In zoos and other private collections, spiny-necked monitors live on average approximately 7.5 years. [9]

Diet

Similarly to most other monitor species, this species is carnivorous, consuming insects, other invertebrates, and birds. [10]

They feed on megapode eggs and on fish, often emerging from the bush. In the intertidal zone at low tide, it is possible that they would search for dead fish.[ citation needed ]

Relationship with humans

During the 1990s, many V. spinulosus were imported under the common name “mangrove monitor” due to increased desirability in the pet trade.

Related Research Articles

<span class="mw-page-title-main">Monitor lizard</span> Genus of reptiles

Monitor lizards are lizards in the genus Varanus, the only extant genus in the family Varanidae. They are native to Africa, Asia, and Oceania, and one species is also found in the Americas as an invasive species. About 80 species are recognized.

<span class="mw-page-title-main">Mangrove monitor</span> Species of lizard

The mangrove monitor, mangrove goanna, or Western Pacific monitor lizard is a member of the monitor lizard family with a large distribution from northern Australia and New Guinea to the Moluccas and Solomon Islands. It grows to lengths of 3.5 to 4 ft.

<span class="mw-page-title-main">Emerald tree monitor</span> Species of lizard

The emerald tree monitor or green tree monitor, is a small to medium-sized arboreal monitor lizard. It is known for its unusual coloration, which consists of shades from green to turquoise, topped with dark, transversedorsal banding. This coloration helps camouflage it in its arboreal habitat. Its color also makes the emerald tree monitor highly prized in both the pet trade and zoos alike.

<span class="mw-page-title-main">Peacock monitor</span> Species of lizard

The peacock monitor, also known commonly as Auffenberg's monitor, is a species of small monitor lizard in the family Varanidae. The species, which belongs to the subgenus Odatria, is endemic to Rote Island, Indonesia.

<span class="mw-page-title-main">Golden-spotted tree monitor</span> Species of lizard

The golden-spotted tree monitor, also known commonly as the golden speckled tree monitor, is a species of monitor lizard in the family Varanidae. The species is endemic to Waigeo Island in Indonesia.

<span class="mw-page-title-main">Peach-throated monitor</span> Species of lizard

The peach-throated monitor, also known commonly as the Sepik monitor, is a species of monitor lizard in the family Varanidae. The species is native to New Guinea.

<span class="mw-page-title-main">Turquoise monitor</span> Species of lizard

The turquoise monitor is a species of monitor lizards found in Indonesia. Specifically, it is found on Halmahera Island and in the Maluku Islands.

<span class="mw-page-title-main">Ceram mangrove monitor</span> Species of lizard

The Ceram mangrove monitor is a species of monitor lizards found in Indonesia. Specifically, it is found on some of the central Moluccan Islands including: Ambon, Seram, Obi, Buru, and Banda. On Ambon and probably on New Guinea V. cerambonensis occurs sympatrically with Varanus indicus. It is in the indicus species group of the subgenus Euprepiosaurus.

<span class="mw-page-title-main">Blue-tailed monitor</span> Species of lizard

The blue-tailed monitor, blue-tailed tree monitor or Kalabeck's monitor, is a monitor lizard of the Varanidae family. It belongs to the V. doreanus group of the subgenus Euprepiosaurus.

The sago monitor or torch monitor is a species of monitor lizards endemic to the Indonesian island of Sanana.

Varanus keithhornei, commonly known as the canopy goanna, Keith Horne's monitor, blue-nosed tree monitor, or Nesbit River monitor, is a species of monitor lizards native to northeast Australia. It is a member of the Varanus prasinus species group.

Finsch's monitor is a species of monitor lizard in the family Varanidae. The species is native to New Guinea and Australia.

The Rennell Island monitor is a species of monitor lizards found in the Solomon Islands archipelago. It is also known as the Hakoi Monitor. It belongs to the subgenus Euprepiosaurus along with the canopy goanna, the peach-throated monitor, Kalabeck's monitor, and others.

Varanus telenesetes, the mysterious tree monitor, is an enigmatic monitor lizard that may actually represent a colour faded specimen of the green tree monitor. The species was described based on a single specimen supposedly collected on Rossel Island in the Louisiade Archipelago of Papua New Guinea. However, later searches of this island have failed to turn up any specimens and native islanders deny ever seeing it. It is now believed that the original collection data was in error and that the species occurs on some other, currently unknown, island east of New Guinea.

Varanus rainerguentheri, also commonly known as Günther's mangrove monitor and Rainer Günther's monitor, is a species of lizard in the family Varanidae. The species is endemic to the Moluccas.

<i>Varanus reisingeri</i> Species of lizard

Varanus reisingeri, known commonly as Reisinger's tree monitor and the Yellow tree monitor, is a species of monitor lizard in the family Varanidae. The species is endemic to Indonesia. It was at one point at least considered an allopatric insular subspecies of the green tree monitor, due to physical and genetic similarities.

Bogert's monitor is a species of tree-dwelling lizard in the family Varanidae. The species is native to Papua New Guinea.

<span class="mw-page-title-main">Bennett's long-tailed monitor</span> Species of lizard

Bennett's long-tailed monitor is a species of monitor lizard in the family Varanidae. It is found in Palau, the Federated States of Micronesia, and the Northern Mariana Islands.

<i>Varanus <span style="font-style:normal;">(</span>Hapturosaurus<span style="font-style:normal;">)</span></i> Subgenus of reptiles

Hapturosaurus, sometimes known as the tree monitors, is a subgenus of lizards, consisting of slender-bodied arboreal monitor lizards mostly found in the tropical rainforests of Indonesia and Papua New Guinea.

<span class="mw-page-title-main">Mariana monitor</span> Species of lizard

Varanus tsukamotoi, the Mariana monitor or Saipan monitor, is a species of lizard of the Varanidae family. It is endemic to the Northern Mariana Islands and Guam, and has been introduced to Japtan in the Marshall Islands.

References

  1. 1 2 3 Allison, A.; Hamilton, A.; Tallowin, O. (2013). "Varanus spinulosus". IUCN Red List of Threatened Species . 2013: e.T196662A2472069. doi: 10.2305/IUCN.UK.2013-1.RLTS.T196662A2472069.en . Retrieved 20 November 2021.
  2. 1 2 3 Varanus spinulosus at the Reptarium.cz Reptile Database. Accessed 230 April 2020.
  3. ↑ "Spiny-neck monitor". reptilesmagazine.com. Retrieved 23 April 2020.
  4. ↑ Sprackland, Robert (28 December 1994). "Rediscovery and taxonomic review of Varanus indicus spinulosus Mertens, 1941". Herpetofauna. 24 (2): 33–38.
  5. ↑ Koch, Andre (November 2010). "Updated checklist of the living monitor lizards of the world (Squamata: Varanidae)". Bonn Zoological Bulletin. 57 (2): 127–136. S2CID   87945208.
  6. 1 2 Bucklitsch, Yannick; BöHme, Wolfgang; Koch, André (17 August 2016). "Scale Morphology and Micro-Structure of Monitor Lizards (Squamata: Varanidae: Varanus spp.) and their Allies: Implications for Systematics, Ecology, and Conservation". Zootaxa. 4153 (1): 1–192. doi:10.11646/zootaxa.4153.1.1. PMID   27615821.
  7. 1 2 Brennan, Ian G.; Lemmon, Alan R.; Lemmon, Emily Moriarty; Portik, Daniel M.; Weijola, Valter; Welton, Luke; Donnellan, Stephen C.; Keogh, J. Scott (3 February 2020). "Phylogenomics of monitor lizards and the role of competition in dictating body size disparity". bioRxiv   10.1101/2020.02.02.931188 .
  8. 1 2 Sprackland, Robert George (1995). Evolution, systematics, and variation of Pacific mangrove monitor lizards (Reptilia: Squamata: Varanidae) (Thesis). ProQuest   1777527055.[ page needed ]
  9. ↑ Mendyk, Robert W. (March 2015). "Life expectancy and longevity of varanid lizards (Reptilia:Squamata:Varanidae) in North American zoos". Zoo Biology. 34 (2): 139–152. doi: 10.1002/zoo.21195 . PMID   25503984.
  10. ↑ Arbuckle, Kevin (2009). "Ecological function of venom in Varanus, with a compilation of dietary records from the literature". Biawak. 3 (2): 46–56. S2CID   90554179.
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