Virgin Islands dwarf sphaero: Difference between revisions

Virgin Islands dwarf sphaero
Conservation status
	Not evaluated (IUCN 3.1)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Suborder:	Lacertilia
Family:	Gekkonidae
Subfamily:	Gekkoninae
Genus:	Sphaerodactylus
Species:	S. parthenopion
Binomial name
	Sphaerodactylus parthenopion; Thomas, 1965
	General distribution of; Sphaerodactylus parthenopion

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The Virgin Islands dwarf sphaero or Virgin Islands dwarf gecko (Sphaerodactylus parthenopion) is a species of gecko and also one of the smallest terrestrial vertebrates. It has only been found on three of the British Virgin Islands: Virgin Gorda, Tortola, and Moskito Island (also spelled "Mosquito Island"). It was discovered in the summer of 1964 and is suspected to be a close relative of Sphaerodactylus nicholsi, a dwarf sphaero from the nearby island of Puerto Rico. It shares its range with the big-scaled least gecko (S. macrolepis), which is found in leaf litter. Unlike this larger gecko, the Virgin Islands dwarf sphaero lives on drier hillsides, yet prefers moist microhabitats found under rocks because it lacks the adaptations necessary for preventing water loss, which is a significant problem due to its small body size.

The Virgin Islands dwarf sphaero has a deep brown color on its upper side, often with a speckling of darker scales. On average, it measures 18 mm (0.71 in) from its snout to its vent, and is nearly as small as a U.S. dime. At most, it weighs 0.15 g (0.0053 oz). There are several stripes or bars of lighter coloration behind its eyes and at the top of its neck that help distinguish it. There are no differences in coloration between males and females, although females are slightly larger in size. Its tail will regenerate when broken off.

Little is known about its population size or its biology. Due to concerns for its survival, the Virgin Islands dwarf sphaero became the focus of attention in early 2011 when Sir Richard Branson announced plans to introduce lemurs to Moskito Island as part of a conservation program. Due to ecological concerns, the plans were put on hold until further studies could demonstrate that the plans were safe for both the Virgin Islands dwarf sphaero and the lemurs.

Taxonomy

The Virgin Islands dwarf sphaero, also referred to as the Virgin Islands dwarf gecko,^[2] was first discovered in the summer of 1964 by biologist Richard Thomas during a collecting trip along the dry, wooded slopes of Virgin Gorda in the British Virgin Islands. The holotype for Sphaerodactylus parthenopion, MCZ 77211, was an adult female collected on 12 August 1964 on a hillside above Pond Bay. A total of eight paratypes were collected on Virgin Gorda and used to describe the new species.^[3]

Classified as a species of dwarf sphaero or dwarf gecko (genus Sphaerodactylus), it is characterized not only by its small body size, but also by a distinctive scale coloration pattern on its head, scales that are small but keeled (having a center ridge) and imbricate on its upper (dorsal) side; a generally uniform dark coloration of the dorsal side, a lack of granular scales on the mid-dorsal area, and a lack of coloration patterns around the shoulders (scapular region) and the pelvis (sacral region).^[4]

Despite striking differences in appearance, S. parthenopion may be most closely related to S. nicholsi.^[5] Like the diminutive S. parthenopion in the Virgin Islands, S. nicholsi is very small and considered the smallest endemic sphaerodactylid in Puerto Rico.^[6] The geographic range of another species, S. townsendi, divides these two closely related populations, suggesting that S. townsendi evolved after S. parthenopion and S. nicholsi diverged.^[5]

Description

The Virgin Islands dwarf sphaero is one of the smallest known amniotes (which includes 23,000 species of reptiles, birds, and mammals),^[7] with an average body size (measured as the snout-vent length or SVL) of 18 mm (0.71 in) and a maximum body mass of 0.15 g (0.0053 oz),^[8] but ranging as low as 0.043 g (0.0015 oz) and averaging 0.117 g (0.0041 oz).^[9] The only known amniote that is smaller is the closely related S. ariasae, which measures 16 mm (0.63 in) and weighs a maximum of 0.14 g (0.0049 oz).^[8]

Typically, the species has a deep brown coloration on the dorsal side and legs, often with a scattering or a fine pattern of interconnected darker scales. The species has a preocular transverse bar (a line of colored scales in front of the eyes at the base of the snout), although it can be hard to see in some individuals.^[1]^[11]^[12] Along each side and directly behind the eyes, a narrow, dark-edged, yellow-brown postocular stripe crosses the temple and fades out near the base of the head. In the occipital region, on top of the head behind the eyes, an almost oval-shaped, dark-edged, yellow-brown bar stretches from one side of the head to the other and someones connects with the postocular stripes. The dark brown scales on the dorsal side crosses over to the ventral side (underside) and fades out, although many scales retain dark edges. The ventral side ranges from a light gray or cream. The tail is mostly yellowish-brown with occasional clusters or short lines of darker scales. The gular (throat) pattern has faint to bold lines of light scales running laterally.^[1]^[4]^[12]

There is no sexual dichromatism (coloration differences between genders) in this species,^[1]^[12] although females may be larger than males, with the SVL of females averaging 18 mm (0.71 in), but only 16 mm (0.63 in) in males.^[1] The snout is moderate in length and blunt.^[1]^[12] The tail regenerates if broken off.^[4]

A yellow-brown stripe extends behind the eyes and over each temple, and then fades out at the base of the head.

The dorsal scales are generally small, acute, keeled, imbricate, and flattened, while the throat and pectoral scales (chest) are keeled.^[1]^[12]^[13] Granular (bumpy) scales are found on the top of the head and the anterior neck, while the scales on the middle of the neck are keeled, acute, flattened, and imbricate.^[1]^[13] In the middle of the back, there is some crowding and size reduction in the scales, and none of these scales are granular (appear bumpy).^[1]^[12]^[13] On the dorsal side of the tail, the scales are acute, keeled, imbricate, and flattened. On the underside of the tail, the scales are smooth, rounded, and enlarged towards the center of the tail (mid-ventrally).^[12] The ventral scales are rounded, smooth, cycloid (have a smooth outer edge), and imbricate.^[1]^[12]^[13] The scales on the ventral caudal (head) scales are smooth, cycloid, enlarged mid-ventrally.^[1]

The count of dorsal scales, from axilla (armpit) to groin, averages 32 with a range of 30 to 35.^[1]^[12]^[13] The ventral count from axilla to groin along the midventral line averages 28 scales and ranges between 26 and 29.^[1]^[12] The scales around the midbody average approximately 52 and range from 50 to 55.^[1]^[12]^[13] There are two postnasals^[1] and one to three (usually two) internasal scales. There are two to three (usually three) scales from the upper lip to the eye (upper labials).^[1]^[12]^[13] On the forth toe of the right foot, there are eight or nine (usually eight) lamellae, or plate-like scales that provide traction for geckos.^[12]^[13] The escutcheons (scales around the genital region) are relatively small and only slightly extend onto the thighs, varying from three to five scales in length and 11 to 13 scales in width.^[1]^[12]^[13]

Distribution and habitat

Originally found only on the island of Virgin Gorda,^[4] it has since been reported on Tortola^[2]^[14] and Moskito Island.^[2]^[15] Its range is sometimes conservatively estimated to encompass the entire British Virgin Islands,^[1] although the original expedition by Thomas did not find any specimens on Tortola, Anegada, and other smaller islands, nor in the United States Virgin Islands, particularly Saint Croix, Saint Thomas, Saint John.^[16] Its distribution is considered unusual because despite its separation from S. nicholsi in Puerto Rico, the Puerto Rican Crested Toad (Bufo lemur) has a geographic range that includes both islands.^[17]

The Virgin Islands dwarf sphaero appears to favor dry (xeric) scrub forests—often mixed with cacti and thorny scrub—on rocky hillsides. It has been found at sea level, although not on the beach among the seaweed litter or in piles of rotting palm debris in the littoral zone, like the more abundant and larger big-scaled least gecko (S. macrolepis) with which it shares its range.^[5]^[16] Also unlike the big-scaled least gecko, they do not "swarm" in the leaf litter, but are only uncommonly found hiding under rocks,^[16] which are considered moist or mesic microhabitats within their dry ecological niche.^[18]^[19]

Ecology and behavior

Like other dwarf sphaeros or dwarf geckos of the genus Sphaerodactylus, little is known about the ecology and behavior of the Virgin Islands dwarf sphaero.^[2]^[6]^[20] Because of its high surface-area-to-volume ratio that results from its diminutive size, the species was thought to be susceptible to water loss, so it has been studied to understand how it survives in its semi-arid habitat.^[9]^[19] Unlike desert-dwelling lizards, the Virgin Islands dwarf sphaero lacks special adaptations to prevent dessication and loses water at a rate similar to that of lizards from mesic habitats.^[18]^[19] From size differences alone, it loses water 70% faster than the larger and sympatric big-scaled least gecko.^[21] It survives instead by inhabiting humid microhabitats in its dry environment, by adjusting it reproductive cycle so that hatchlings emerge during the time of year with the highest precipitation,^[18]^[19] and by reducing activity during the driest parts of the day.^[21]

Conservation

Too little data has been gathered to assess the population size and trend of the Virgin Islands dwarf sphaero.^[2] It has been reported as "moderately common," although difficult to find because of its size and ability to blend in to its surroundings.^[22] Its distribution across the British Virgin Islands seems to be limited, and development may affect it further.^[2]

In early 2011, the Virgin Islands dwarf sphaero gained international attention when Sir Richard Branson announced plans to introduce lemurs—endangered primates from Madagascar—to Moskito Island as part of a captive breeding project for conservation purposes.^[23] Biologists, conservationists, and the general public quickly voiced concerns over the impact that would have on the native species of the island.^[24] In particular, people feared that the lemurs would wipe out the local population of Virgin Islands dwarf sphaeros,^[25] which was referred to as "one of the world's rarest lizards",^[25] because of the lemurs' "aggressive, omnivorous" behavior.^[23] Other researchers instead focused on concerns about the lemurs' ability to thrive^[26] or the pathogens they might introduce.^[27] The leader of Branson's environmental impact assessment agreed that caution was needed with the introduction, even before the plans to introduce the lemurs were announced.^[25] Regarding the Virgin Islands dwarf sphaero, Branson stated that the concerns were misplaced because lemurs mostly eat plant material and would rarely eat geckos if any at all.^[23]^[27] However, Branson ultimately backed down, stating, "I will keep the lemurs enclosed whilst we get experts to conduct further surveys on geckos and particularly the dwarf geckos. If these studies indicate any real risk to these geckos, we will keep the lemurs enclosed."^[23]

References

^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s Schwartz & Henderson 1991, p. 522.
^ ^a ^b ^c ^d ^e ^f Perry & Gerber 2006, p. 243.
^ Thomas 1965, pp. 117–118.
^ ^a ^b ^c ^d Thomas 1965, p. 118.
^ ^a ^b ^c Thomas & Schwartz 1966, p. 248.
^ ^a ^b López-Ortiz & Lewis 2002, p. 276.
^ Hedges & Thomas 2001, p. 168.
^ ^a ^b Hedges & Thomas 2001, p. 172.
^ ^a ^b MacLean 1985, p. 759.
^ Trivedi, B. P. (3 December 2001). "Smallest known lizard found in Caribbean". National Geographic News.
^ Thomas 1965, p. 119.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ Thomas & Schwartz 1966, pp. 247–248.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Thomas 1965, pp. 118–119.
^ Procter & Fleming 1999, p. 50.
^ Heatwole, Levins & Byer 1981, p. 49.
^ ^a ^b ^c Thomas 1965, p. 121.
^ Carey 1972, p. 87.
^ ^a ^b ^c López-Ortiz & Lewis 2004, p. 438.
^ ^a ^b ^c ^d Hedges & Thomas 2001, pp. 172–173.
^ Nava et al. 2001, p. 456.
^ ^a ^b MacLean 1985, p. 761.
^ MacLean 1985, p. 760.
^ ^a ^b ^c ^d Harrison, D. (7 May 2011). "Branson retreats in row over lemurs plan for 'eco-island'". The Telegraph.
^ Zielinski, S. (19 April 2011). "Billionaire Branson to release lemurs on Caribbean island". Smithsonian Media.
^ ^a ^b ^c Harrison, D. (16 Apr 2011). "Sir Richard Branson's 'eco-island' plans hit by row over non-native lemurs". The Telegraph.
^ "Sir Richard's possible folly". Duke University. 22 April 2011.
^ ^a ^b Carroll, R. (18 April 2011). "Richard Branson to create sanctuary for lemurs - 8,000 miles from their home". Guardian News.

Literature cited

Carey, W. M. (1972). "The herpetology of Anegada, British Virgin Islands" (PDF). Caribbean Journal of Science. 12 (l–2): 79–89. {{cite journal}}: Invalid |ref=harv (help)
Heatwole, H.; Levins, R.; Byer, M. D. (1981). Biogeography of the Puerto Rican Bank (PDF). Atoll research bulletin, no. 251. Washington, D.C.: Smithsonian Institution. OCLC 33148490. {{cite book}}: Invalid |ref=harv (help)
Hedges, S. B.; Thomas, R. (2001). "At the lower size limit in amniote vertebrates: a new diminutive lizard from the West Indies" (PDF). Caribbean Journal of Science. 37 (3–4): 168–173. {{cite journal}}: Invalid |ref=harv (help)
Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi: 10.1670/0022-1511(2002)036[0276:SAOHAG]2.0.CO;2, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi= 10.1670/0022-1511(2002)036[0276:SAOHAG]2.0.CO;2 instead.
Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi: 10.1655/03-84, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi= 10.1655/03-84 instead.
Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi: 10.1016/0300-9629(85)90479-7, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi= 10.1016/0300-9629(85)90479-7 instead.
Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi: 10.1163/15685380152770417, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi= 10.1163/15685380152770417 instead.
Perry, G.; Gerber, G. P. (2006). "Conservation of amphibians and reptiles in the British Virgin Islands: Status and patterns" (PDF). Applied Herpetology. 3: 237–256. {{cite journal}}: Invalid |ref=harv (help)
Procter, L. V; Fleming, eds. (1999). Biodiversity: the UK Overseas Territories (PDF). Peterborough: Joint Nature Conservation Committee. ISBN 978-1-861-07502-4. OCLC 44147511. {{cite book}}: Invalid |ref=harv (help)
Schwartz, A.; Henderson, R. W. (1991). Amphibians and Reptiles of the West Indies. Gainesville: University of Florida. {{cite book}}: Invalid |ref=harv (help)
Thomas, R. (1965). "A new gecko from the Virgin Islands". Quarterly Journal of the Florida Academy of Sciences. 28 (1): 117–122. {{cite journal}}: Invalid |ref=harv (help)
Thomas, R.; Schwartz, A. (1966). Sphaerodactylus (Gekkonidae) in the greater Puerto Rico region. Vol. 10. Gainesville: University of Florida. pp. 193–260. {{cite book}}: |journal= ignored (help); Invalid |ref=harv (help)

@@ Line 1: / Line 1: @@
 {{Taxobox
-| name = Virgin Islands Dwarf Sphaero
+| name = Virgin Islands dwarf sphaero
+| image = Sphaerodactylus parthenopion 002.jpg
+| status = NE
+| status_system = iucn3.1
 | regnum = [[Animal]]ia
 | phylum = [[Chordate|Chordata]]
@@ Line 11: / Line 14: @@
 | species = '''''S. parthenopion'''''
 | binomial = ''Sphaerodactylus parthenopion''
-| binomial_authority = Thomas, 1965 <ref>[http://reptile-database.reptarium.cz/species.php?genus=Sphaerodactylus&species=parthenopion JCVI.prg] (Viewed February 15, 2010.)</ref>
+| binomial_authority = Thomas, 1965{{Sfn|Schwartz|Henderson|1991|p=522}}
-| synonyms = }}
+| synonyms =
+| range_map = LocationBritishVirginIslands.png
+| range_map_alt = Map of British Virgin Islands southeast of the North American mainland and east of Puerto Rico.
+| range_map_caption = General distribution of<br>''Sphaerodactylus parthenopion''{{Sfn|Schwartz|Henderson|1991|p=522}}
+}}
+The '''Virgin Islands dwarf sphaero''' or '''Virgin Islands dwarf gecko''' (''Sphaerodactylus parthenopion'') is a species of [[gecko]] and also one of the [[Smallest organisms|smallest terrestrial vertebrates]].  It has only been found on three of the [[British Virgin Islands]]: [[Virgin Gorda]], [[Tortola]], and [[Mosquito Island|Moskito Island]] (also spelled "Mosquito Island").  It was discovered in the summer of 1964 and is suspected to be a close relative of ''[[Sphaerodactylus nicholsi]]'', a [[Sphaerodactylus|dwarf sphaero]] from the nearby island of [[Puerto Rico]].  It shares its range with the [[big-scaled least gecko]] (''S.&nbsp;macrolepis''), which is found in leaf litter.  Unlike this larger gecko, the Virgin Islands dwarf sphaero lives on drier hillsides, yet prefers moist [[Habitat|microhabitats]] found under rocks because it lacks the [[adaptation]]s necessary for preventing water loss, which is a significant problem due to its small body size.
-The '''Virgin Gorda Least Gecko''' or '''Virgin Islands Dwarf Sphaero''' is a species of [[gecko]] found in the [[British Virgin Islands]].
-This species along with fellow [[Sphaerodactylus|Sphaero gecko]], ''[[Sphaerodactylus ariasae]]'', are not only the world's smallest [[lizard]]s, but the world's [[smallest_organisms|smallest terrestrial]] [[vertebrate]]s. <ref>[http://news.nationalgeographic.com/news/2001/12/1203_TVtinylizard.html National Geographic Online]  (Viewed February 15, 2010.)</ref><ref>[http://www.kingsnake.com/westindian/metazoa10.html Kingsnake.com]  (Viewed February 15, 2010.) </ref><ref>http://www.oddee.com/item_96492.aspx (Viewed February 15, 2010.) </ref>
+The Virgin Islands dwarf sphaero has a deep brown color on its upper side, often with a speckling of darker scales.  On average, it measures {{convert|18|mm|in|abbr=on}} from its [[snout]] to its [[Cloaca|vent]], and is nearly as small as a [[Dime (United States coin)|U.S. dime]].  At most, it weighs {{convert|0.15|g|oz|abbr=on}}.  There are several stripes or bars of lighter coloration behind its eyes and at the top of its neck that help distinguish it.  There are no differences in coloration between males and females, although females are slightly larger in size.  Its tail will regenerate when broken off.
+Little is known about its population size or its biology.  Due to concerns for its survival, the Virgin Islands dwarf sphaero became the focus of attention in early 2011 when [[Richard Branson|Sir Richard Branson]] announced plans to introduce [[lemur]]s to Moskito Island as part of a conservation program.  Due to ecological concerns, the plans were put on hold until further studies could demonstrate that the plans were safe for both the Virgin Islands dwarf sphaero and the lemurs.
+==Taxonomy==
+The Virgin Islands dwarf sphaero, also referred to as the Virgin Islands dwarf gecko,{{Sfn|Perry|Gerber|2006|p=243}} was first discovered in the summer of 1964 by [[Biology|biologist]] Richard Thomas during a collecting trip along the dry, wooded slopes of [[Virgin Gorda]] in the [[British Virgin Islands]].  The [[holotype]] for ''Sphaerodactylus parthenopion'', MCZ 77211, was an adult female collected on 12 August 1964 on a hillside above Pond Bay.  A total of eight [[paratype]]s were collected on Virgin Gorda and used to describe the new species.{{Sfn|Thomas|1965|pp=117–118}}
+Classified as a species of [[Sphaerodactylus|dwarf sphaero]] or dwarf [[gecko]] ([[genus]] ''Sphaerodactylus''), it is characterized not only by its small body size, but also by a distinctive scale coloration pattern on its head, [[Scale (anatomy)|scales]] that are small but keeled (having a center ridge) and [[wikt:imbricate|imbricate]] on its upper ([[Dorsum (anatomy)|dorsal]]) side; a generally uniform dark coloration of the dorsal side, a lack of granular scales on the mid-dorsal area, and a lack of coloration patterns around the shoulders (scapular region) and the pelvis (sacral region).{{Sfn|Thomas|1965|p=118}}
+Despite striking differences in appearance, ''S.&nbsp;parthenopion'' may be most closely related to ''[[Sphaerodactylus nicholsi|S.&nbsp;nicholsi]]''.{{Sfn|Thomas|Schwartz|1966|p=248}}  Like the diminutive ''S.&nbsp;parthenopion'' in the Virgin Islands, ''S.&nbsp;nicholsi'' is very small and considered the smallest endemic sphaerodactylid in [[Puerto Rico]].{{Sfn|López-Ortiz|Lewis|2002|p=276}}  The geographic range of another species, ''[[Sphaerodactylus townsendi|S.&nbsp;townsendi]]'', divides these two closely related populations, suggesting that ''S.&nbsp;townsendi'' evolved after ''S.&nbsp;parthenopion'' and ''S.&nbsp;nicholsi'' [[Genetic divergence|diverged]].{{Sfn|Thomas|Schwartz|1966|p=248}}
+==Description==
+The Virgin Islands dwarf sphaero is one of the smallest known [[amniote]]s (which includes 23,000&nbsp;species of reptiles, birds, and mammals),{{Sfn|Hedges|Thomas|2001|p=168}} with an average body size (measured as the [[snout]]-[[Cloaca|vent]] length or SVL) of {{convert|18|mm|in|abbr=on}} and a maximum body mass of {{convert|0.15|g|oz|abbr=on}},{{Sfn|Hedges|Thomas|2001|p=172}} but ranging as low as {{convert|0.043|g|oz|abbr=on}} and averaging {{convert|0.117|g|oz|abbr=on}}.{{Sfn|MacLean|1985|p=759}}  The only known amniote that is smaller is the closely related ''[[Sphaerodactylus ariasae|S.&nbsp;ariasae]]'', which measures {{convert|16|mm|in|abbr=on}} and weighs a maximum of {{convert|0.14|g|oz|abbr=on}}.{{Sfn|Hedges|Thomas|2001|p=172}}
+[[File:Sphaerodactylus parthenopion 004.jpg|left|thumb|alt=|The Virgin Islands dwarf sphaero is nearly as small as a [[Dime (United States coin)|U.S. dime]].{{r|NatGeo_03Dec2001}}]]
+Typically, the species has a deep brown coloration on the dorsal side and legs, often with a scattering or a fine pattern of interconnected darker scales.  The species has a preocular transverse bar (a line of colored scales in front of the eyes at the base of the snout), although it can be hard to see in some individuals.{{Sfn|Schwartz|Henderson|1991|p=522}}{{Sfn|Thomas|1965|p=119}}{{Sfn|Thomas|Schwartz|1966|pp=247–248}}  Along each side and directly behind the eyes, a narrow, dark-edged, yellow-brown postocular stripe crosses the temple and fades out near the base of the head.  In the occipital region, on top of the head behind the eyes, an almost oval-shaped, dark-edged, yellow-brown bar stretches from one side of the head to the other and someones connects with the postocular stripes.  The dark brown scales on the dorsal side crosses over to the ventral side (underside) and fades out, although many scales retain dark edges.  The ventral side ranges from a light gray or cream.  The tail is mostly yellowish-brown with occasional clusters or short lines of darker scales.  The gular (throat) pattern has faint to bold lines of light scales running [[wikt:lateral|laterally]].{{Sfn|Schwartz|Henderson|1991|p=522}}{{Sfn|Thomas|1965|p=118}}{{Sfn|Thomas|Schwartz|1966|pp=247–248}}
+There is no [[Sexual dimorphism|sexual dichromatism]] (coloration differences between genders) in this species,{{Sfn|Schwartz|Henderson|1991|p=522}}{{Sfn|Thomas|Schwartz|1966|pp=247–248}} although females may be larger than males, with the SVL of females averaging {{convert|18|mm|in|abbr=on}}, but only {{convert|16|mm|in|abbr=on}} in males.{{Sfn|Schwartz|Henderson|1991|p=522}}  The snout is moderate in length and blunt.{{Sfn|Schwartz|Henderson|1991|p=522}}{{Sfn|Thomas|Schwartz|1966|pp=247–248}}  The tail regenerates if broken off.{{Sfn|Thomas|1965|p=118}}
+[[File:Sphaerodactylus parthenopion 003.jpg|thumb|right|alt=Close-up left profile of a Virgin Islands dwarf sphaero|A yellow-brown stripe extends behind the eyes and over each temple, and then fades out at the base of the head.]]
+The dorsal scales are generally small, acute, keeled, imbricate, and flattened, while the throat and pectoral scales (chest) are keeled.{{Sfn|Schwartz|Henderson|1991|p=522}}{{Sfn|Thomas|Schwartz|1966|pp=247–248}}{{Sfn|Thomas|1965|pp=118–119}}  Granular (bumpy) scales are found on the top of the head and the [[wikt:anterior|anterior]] neck, while the scales on the middle of the neck are keeled, acute, flattened, and imbricate.{{Sfn|Schwartz|Henderson|1991|p=522}}{{Sfn|Thomas|1965|pp=118–119}}  In the middle of the back, there is some crowding and size reduction in the scales, and none of these scales are granular (appear bumpy).{{Sfn|Schwartz|Henderson|1991|p=522}}{{Sfn|Thomas|Schwartz|1966|pp=247–248}}{{Sfn|Thomas|1965|pp=118–119}}  On the dorsal side of the tail, the scales are acute, keeled, imbricate, and flattened.  On the underside of the tail, the scales are smooth, rounded, and enlarged towards the center of the tail (mid-ventrally).{{Sfn|Thomas|Schwartz|1966|pp=247–248}}  The ventral scales are rounded, smooth, cycloid (have a smooth outer edge), and imbricate.{{Sfn|Schwartz|Henderson|1991|p=522}}{{Sfn|Thomas|Schwartz|1966|pp=247–248}}{{Sfn|Thomas|1965|pp=118–119}}  The scales on the ventral caudal (head) scales are smooth, cycloid, enlarged mid-ventrally.{{Sfn|Schwartz|Henderson|1991|p=522}}
+The count of dorsal scales, from axilla (armpit) to groin, averages 32 with a range of 30 to 35.{{Sfn|Schwartz|Henderson|1991|p=522}}{{Sfn|Thomas|Schwartz|1966|pp=247–248}}{{Sfn|Thomas|1965|pp=118–119}}  The ventral count from axilla to groin along the [[midventral line]] averages 28 scales and ranges between 26 and 29.{{Sfn|Schwartz|Henderson|1991|p=522}}{{Sfn|Thomas|Schwartz|1966|pp=247–248}}  The scales around the midbody average approximately 52 and range from 50 to 55.{{Sfn|Schwartz|Henderson|1991|p=522}}{{Sfn|Thomas|Schwartz|1966|pp=247–248}}{{Sfn|Thomas|1965|pp=118–119}}  There are two [[Nasal scale|postnasals]]{{Sfn|Schwartz|Henderson|1991|p=522}} and one to three (usually two) [[internasal scales]].  There are two to three (usually three) scales from the upper lip to the eye (upper labials).{{Sfn|Schwartz|Henderson|1991|p=522}}{{Sfn|Thomas|Schwartz|1966|pp=247–248}}{{Sfn|Thomas|1965|pp=118–119}}  On the forth toe of the right foot, there are eight or nine (usually eight) [[Lamella (anatomy)|lamellae]], or plate-like scales that provide traction for geckos.{{Sfn|Thomas|Schwartz|1966|pp=247–248}}{{Sfn|Thomas|1965|pp=118–119}}  The escutcheons (scales around the genital region) are relatively small and only slightly extend onto the thighs, varying from three to five scales in length and 11 to 13 scales in width.{{Sfn|Schwartz|Henderson|1991|p=522}}{{Sfn|Thomas|Schwartz|1966|pp=247–248}}{{Sfn|Thomas|1965|pp=118–119}}
+{{-}}
+==Distribution and habitat==
+Originally found only on the island of Virgin Gorda,{{Sfn|Thomas|1965|p=118}} it has since been reported on [[Tortola]]{{Sfn|Perry|Gerber|2006|p=243}}{{Sfn|Procter|Fleming|1999|p=50}} and [[Mosquito Island|Moskito Island]].{{Sfn|Perry|Gerber|2006|p=243}}{{Sfn|Heatwole|Levins|Byer|1981|p=49}}  Its range is sometimes conservatively estimated to encompass the entire British Virgin Islands,{{Sfn|Schwartz|Henderson|1991|p=522}} although the original expedition by Thomas did not find any specimens on Tortola, [[Anegada]], and other smaller islands, nor in the [[United States Virgin Islands]], particularly [[Saint Croix, U.S. Virgin Islands|Saint Croix]], [[Saint Thomas, U.S. Virgin Islands|Saint Thomas]], [[Saint John, U.S. Virgin Islands|Saint John]].{{Sfn|Thomas|1965|p=121}}  Its distribution is considered unusual because despite its separation from ''S.&nbsp;nicholsi'' in Puerto Rico, the [[Puerto Rican Crested Toad]] (''Bufo lemur'') has a geographic range that includes both islands.{{Sfn|Carey|1972|p=87}}
+The Virgin Islands dwarf sphaero appears to favor [[Deserts and xeric shrublands|dry (xeric) scrub forests]]—often mixed with [[cactus|cacti]] and thorny scrub—on rocky hillsides.  It has been found at sea level, although not on the beach among the [[seaweed]] litter or in piles of rotting palm debris in the [[littoral zone]], like the more abundant and larger [[big-scaled least gecko]] (''S.&nbsp;macrolepis'') with which it shares its range.{{Sfn|Thomas|Schwartz|1966|p=248}}{{Sfn|Thomas|1965|p=121}}  Also unlike the big-scaled least gecko, they do not "swarm" in the leaf litter, but are only uncommonly found hiding under rocks,{{Sfn|Thomas|1965|p=121}} which are considered moist or [[Mesic habitat|mesic]] microhabitats within their dry [[ecological niche]].{{Sfn|López-Ortiz|Lewis|2004|p=438}}{{Sfn|Hedges|Thomas|2001|pp=172–173}}
+==Ecology and behavior==
+Like other dwarf sphaeros or dwarf geckos of the genus ''Sphaerodactylus'', little is known about the ecology and behavior of the Virgin Islands dwarf sphaero.{{Sfn|Perry|Gerber|2006|p=243}}{{Sfn|López-Ortiz|Lewis|2002|p=276}}{{Sfn|Nava|Lindsay|Henderson|Powell|2001|p=456}}  Because of its high [[surface-area-to-volume ratio]] that results from its diminutive size, the species was thought to be susceptible to water loss, so it has been studied to understand how it survives in its semi-arid habitat.{{Sfn|MacLean|1985|p=759}}{{Sfn|Hedges|Thomas|2001|pp=172–173}}  Unlike desert-dwelling lizards, the Virgin Islands dwarf sphaero lacks special [[adaptation]]s to prevent dessication and loses water at a rate similar to that of lizards from mesic habitats.{{Sfn|López-Ortiz|Lewis|2004|p=438}}{{Sfn|Hedges|Thomas|2001|pp=172–173}}  From size differences alone, it loses water 70% faster than the larger and sympatric big-scaled least gecko.{{Sfn|MacLean|1985|p=761}}  It survives instead by inhabiting humid microhabitats in its dry environment, by adjusting it [[Biological life cycle|reproductive cycle]] so that hatchlings emerge during the time of year with the highest precipitation,{{Sfn|López-Ortiz|Lewis|2004|p=438}}{{Sfn|Hedges|Thomas|2001|pp=172–173}} and by reducing activity during the driest parts of the day.{{Sfn|MacLean|1985|p=761}}
+==Conservation==
+Too little data has been gathered to assess the population size and trend of the Virgin Islands dwarf sphaero.{{Sfn|Perry|Gerber|2006|p=243}}  It has been reported as "moderately common," although difficult to find because of its size and ability to blend in to its surroundings.{{Sfn|MacLean|1985|p=760}}  Its distribution across the British Virgin Islands seems to be limited, and [[Land development|development]] may affect it further.{{Sfn|Perry|Gerber|2006|p=243}}
+In early 2011, the Virgin Islands dwarf sphaero gained international attention when [[Richard Branson|Sir Richard Branson]] announced plans to [[Introduced species|introduce]] [[lemur]]s—endangered [[primate]]s from [[Madagascar]]—to Moskito Island as part of a [[captive breeding]] project for [[Conservation movement|conservation]] purposes.{{r|Telegraph_07May2011}}  Biologists, conservationists, and the general public quickly voiced concerns over the impact that would have on the native species of the island.{{r|Smithsonian_19Apr2011}}  In particular, people feared that the lemurs would wipe out the local population of Virgin Islands dwarf sphaeros,{{r|Telegraph_16Apr2011}} which was referred to as "one of the world's rarest lizards",{{r|Telegraph_16Apr2011}} because of the lemurs' "aggressive, omnivorous" behavior.{{r|Telegraph_07May2011}}  Other researchers instead focused on concerns about the lemurs' ability to thrive{{r|DukeUniv_22Apr2011}} or the [[pathogen]]s they might introduce.{{r|Guardian_18Apr2011}}  The leader of Branson's [[environmental impact assessment]] agreed that caution was needed with the introduction, even before the plans to introduce the lemurs were announced.{{r|Telegraph_16Apr2011}}  Regarding the Virgin Islands dwarf sphaero, Branson stated that the concerns were misplaced because lemurs mostly eat plant material and would rarely eat geckos if any at all.{{r|Telegraph_07May2011|Guardian_18Apr2011}}  However, Branson ultimately backed down, stating, "I will keep the lemurs enclosed whilst we get experts to conduct further surveys on geckos and particularly the dwarf geckos. If these studies indicate any real risk to these geckos, we will keep the lemurs enclosed."{{r|Telegraph_07May2011}}
 ==References==
+<!------------------------------------------------------------
-{{reflist}}
+This article uses list-defined references in conjunction with
+the {{r}} and (possibly) {{Sfn}} templates to keep the body
+text clean. Please follow existing examples within the text
+and refer to the following documentation pages if needed:
+List-defined references:
+http://en.wikipedia.org/wiki/Wikipedia:LDR
+Template {{r}}:
+http://en.wikipedia.org/wiki/Template:R
+Template {{Sfn}}:
+http://en.wikipedia.org/wiki/Template:Sfn
+See http://en.wikipedia.org/wiki/Wikipedia:Footnotes for a
+discussion of different citation methods and how to generate
+footnotes using the <ref> tags.
+------------------------------------------------------------->
+{{Reflist|colwidth=25em|refs=
+<ref name=NatGeo_03Dec2001>{{cite web | last = Trivedi | first = B. P. | title = Smallest known lizard found in Caribbean | url = http://news.nationalgeographic.com/news/2001/12/1203_TVtinylizard.html | publisher = National Geographic News | date = 3 December 2001}}</ref>
+<ref name=Telegraph_07May2011>{{cite web | last = Harrison | first = D. | title = Branson retreats in row over lemurs plan for 'eco-island' | url = http://www.telegraph.co.uk/news/worldnews/centralamericaandthecaribbean/britishvirginislands/8500115/Branson-retreats-in-row-over-lemurs-plan-for-eco-island.html | publisher = The Telegraph | date = 7 May 2011}}</ref>
+<ref name=Telegraph_16Apr2011>{{cite web | last = Harrison | first = D. | title = Sir Richard Branson's 'eco-island' plans hit by row over non-native lemurs | url = http://www.telegraph.co.uk/news/worldnews/centralamericaandthecaribbean/britishvirginislands/8455570/Sir-Richard-Bransons-eco-island-plans-hit-by-row-over-non-native-lemurs.html | publisher = The Telegraph | date = 16 Apr 2011}}</ref>
+<ref name=DukeUniv_22Apr2011>{{cite web | title = Sir Richard's possible folly | url = http://research.duke.edu/blog/2011/04/bransons-love-affair-lemurs | publisher = Duke University | date = 22 April 2011}}</ref>
+<ref name=Guardian_18Apr2011>{{cite web | last = Carroll | first = R. | title = Richard Branson to create sanctuary for lemurs - 8,000 miles from their home | url = http://www.guardian.co.uk/environment/2011/apr/18/richard-branson-lemur-moskito | publisher = Guardian News | date = 18 April 2011}}</ref>
+<ref name=Smithsonian_19Apr2011>{{cite web | last = Zielinski | first = S. | title = Billionaire Branson to release lemurs on Caribbean island | url = http://blogs.smithsonianmag.com/science/2011/04/billionaire-branson-to-release-lemurs-on-caribbean-island | publisher = Smithsonian Media | date = 19 April 2011}}</ref>
+}}
+===Literature cited===
+{{Refbegin}}
+*<!-- {{Sfn|Carey|1972}} -->{{cite journal | last = Carey | first = W. M. | year = 1972 | title = The herpetology of Anegada, British Virgin Islands | journal = Caribbean Journal of Science | volume = 12 | issue = l–2 | pages = 79–89 | url = http://academic.uprm.edu/publications/cjs/VOL12/P079-090.PDF | format = PDF | ref = harv}}
+*<!-- {{Sfn|Heatwole|Levins|Byer|1981}} -->{{cite book | last1 = Heatwole | first1 = H. | last2 = Levins | first2 = R. | last3 = Byer | first3 = M. D. | year = 1981 | title = Biogeography of the Puerto Rican Bank | series = Atoll research bulletin, no. 251 | publisher = Smithsonian Institution | location = 	Washington, D.C. | url = http://coalicionventanaverraco.org/files/Biogeography_of_the_Puerto_Rican_Bank.pdf | format = PDF | oclc = 33148490 | ref = harv}}
+*<!-- {{Sfn|Hedges|Thomas|2001}} -->{{cite journal | last1 = Hedges | first1 = S. B. | last2 = Thomas | first2 = R. | year = 2001 | title = At the lower size limit in amniote vertebrates: a new diminutive lizard from the West Indies | journal = Caribbean Journal of Science | volume = 37 | number = 3–4 | pages = 168–173 | url = http://academic.uprm.edu/publications/cjs/Vol37b/37_168-173.pdf | format = PDF | ref = harv}}
+*<!-- {{Sfn|López-Ortiz|Lewis|2002}} -->{{cite doi | 10.1670/0022-1511(2002)036[0276:SAOHAG]2.0.CO;2}}
+*<!-- {{Sfn|López-Ortiz|Lewis|2004}} -->{{cite doi | 10.1655/03-84}}
+*<!-- {{Sfn|MacLean|1985}} -->{{cite doi | 10.1016/0300-9629(85)90479-7}}
+*<!-- {{Sfn|Nava|Lindsay|Henderson|Powell|2001}} -->{{cite doi | 10.1163/15685380152770417}}
+*<!-- {{Sfn|Perry|Gerber|2006}} -->{{cite journal | last1 = Perry | first1 = G. | last2 = Gerber | first2 = G. P. | year = 2006 | title = Conservation of amphibians and reptiles in the British Virgin Islands: Status and patterns | journal = Applied Herpetology | volume = 3 | pages = 237–256 | url = http://www.rw.ttu.edu/perry/Reprints/06%20BVI%20herps.pdf | format = PDF | ref = harv}}
+*<!-- {{Sfn|Procter|Fleming|1999}} -->{{cite book | editor1-last = Procter | editor1-first = D. | editor2-last = Fleming | editor1-first = L. V | year = 1999 | title = Biodiversity: the UK Overseas Territories | location = Peterborough | publisher = Joint Nature Conservation Committee | isbn = 978-1-861-07502-4 | oclc = 44147511 | url = http://www.jncc.gov.uk/pdf/OT_BVI.pdf | format = PDF | ref = harv}}
+*<!-- {{Sfn|Schwartz|Henderson|1991}} -->{{cite book | last1 = Schwartz | first1 = A. | last2 = Henderson | first2 = R. W. | year = 1991 | title = Amphibians and Reptiles of the West Indies | publisher = University of Florida | location = Gainesville | url = http://books.google.com/books?id=0x_hxEolYUAC&pg=PA522 | ref = harv }}
+*<!-- {{Sfn|Thomas|1965}} -->{{cite journal | last = Thomas | first = R. | year = 1965 | title = A new gecko from the Virgin Islands | journal = Quarterly Journal of the Florida Academy of Sciences | volume = 28 | issue = 1 | pages = 117–122 | ref = harv}}
+*<!-- {{Sfn|Thomas|Schwartz|1966}} -->{{cite book | last1 = Thomas | first1 = R. | last2 = Schwartz | first2 = A. | year = 1966 | title = ''Sphaerodactylus'' (Gekkonidae) in the greater Puerto Rico region | publisher = University of Florida | location = Gainesville | journal = Bulletin of the Florida State Museum, Biological Sciences | volume = 10 | number = 6 | pages = 193–260 | url = http://ufdc.ufl.edu/UF00001539/00001/3j | ref = harv}}
+{{Refend}}
 ==Further reading==
-*http://www.gekkota.com/
-*MacLean, W. P.  1985.  Water-loss rates of Sphaerodactylus parthenopion (Reptilia: Gekkonidae), the smallest amniote vertebrate.  Comparative Biochemistry and Physiology 92A(4): 759-761.
 *MacLean, W.P. 1982. Reptiles and amphibians of the Virgin Islands. MacMillan Caribbean, London:vii +54 pp.
 *Mayer,G.C. & Lazell,J. 1988. Distributional records for reptiles and amphibians from the Puerto Rico Bank. Herp. Rev. 19 91): 23-24
-*Rösler, H. 2000. Kommentierte Liste der rezent, subrezent und fossil bekannten Geckotaxa (Reptilia: Gekkonomorpha). Gekkota 2: 28-153
-*Schwartz,A. & Henderson,R.W. 1991. Amphibians and Reptiles of the West Indies. University of Florida Press, Gainesville, 720 pp.
-*Thomas, R., and A. Schwartz. 1966. Sphaerodactylus (Gekkonidae) in the greater Puerto Rico region. Bulletin of the Florida State Museum, Biological Sciences, 10:193—260
-*Thomas, R. 1965. A new gecko from the Virgin Islands. Quart. Jour. Florida Acad. Sci. 28:117-122.
 [[Category:Geckos]]
 [[Category:Animals described in 1965]]
+[[sv:Sphaerodactylus parthenopion]]