Boulenger's keelback

{{Short description|Species of snake}} {{For|another species called Boulenger's keelback|Hebius boulengeri}} {{Speciesbox | name = Boulenger's keelback | image = Xenochrophis asperrimus.jpg | image_caption = '''''Fowlea asperrimus''''' Taken by: [http://www.wildlifepictures.se Gunnar Pettersson](Wildlife Artist) at Sinharaja, Sri Lanka on 2008-02-19. | status = LC | status_system = IUCN3.1 | status_ref = <ref name=IUCN>{{Cite journal | author1 = de Silva, A. |author2= Wickramasinghe, L.J.M. | name-list-style = amp | title = ''Fowlea asperrimus'' | journal = The IUCN Red List of Threatened Species | volume = 2021 | page = e.T197191A123311972 | publisher = IUCN | date = 2021 | url = https://www.iucnredlist.org/species/197191/123311972 | access-date = 15 January 2021}}</ref> | genus = Fowlea | species = asperrima | authority = (Boulenger, 1891)<ref name="Boulenger"/> | synonyms = *''Tropidonotus asperrimus'' {{small|Boulenger, 1891: 281}} *''Natrix piscator asperrimus'' {{small|— M.A. Smith, 1943}} *''Natrix asperrimus'' {{small|— Taylor, 1950: 567}} *''Xenochrophis asperrimus'' {{small|— Das 1996: 59}} *''Fowlea asperrimus'' {{small|— Purkayastha et al., 2019}} | synonyms_ref = <ref name="Smith"/><ref name=RDB/> }}

'''Boulenger's keelback'''<ref name="Boulenger"/> ('''''Fowlea asperrima'''''), also known commonly as the '''Sri Lankan keelback''',<ref name="IUCN"/> is a species of water snake in the family Colubridae. The species is endemic to Sri Lanka.<ref name="das"/><ref name="Suranjan"/><ref name="Edward"/><ref name=RDB>{{NRDB species|genus=Fowlea |species=asperrima |accessdate=19 January 2016}}</ref>

==Etymology== The common name "Boulenger's keelback" is in honour of Belgian-born British herpetologist George Albert Boulenger.<ref name="JHU"/>

==Habitat== {{see also|Bundala National Park#Fauna}} ''F. asperrima'' is found in Sri Lanka,<ref name="JHU"/><ref name="silva"/><ref name="Wall"/> in both dry and wet climatic zones up to {{convert|1,000|m|ft|abbr=on}} above mean sea level. It is abundant in waterways, such as flooded rice fields, ponds, lakes, marshes, rivers and streams.<ref name="Boulenger"/><ref name="Suranjan"/><ref name="Boulenger2"/>

==Characteristics== The body of ''F. asperrima'' is short and cylindrical, and has a clear neck and slightly pointed head. The eyes have rounded pupils, and the nostrils are narrow, directed slightly upwards. The tail is long. At hatching, it is {{convert|10|cm|in|abbr=on}} long and grows to an adult length of {{convert|40|–|70|cm|in|abbr=on}}. The female is longer.<ref name="Boulenger"/><ref name="Suranjan"/><ref name="Edward"/>

==Scalation== {{see also|Snake scales#Nomenclature of scales}}

''F. asperrima'' has one pair of internasals; the posterior parts are narrow. One loreal, preocular, postocular and three temporals are found. Of the 9 supralabials, 4 and 6 connect with the eye. Ventrals number 131–146, and the undivided subcaudals are 73–93 in count. At midbody there are 19 rows of dorsal scales, which are strongly keeled and rough.<ref name="Vogel"/><ref name="Boulenger"/><ref name="Edward"/><ref name="Boulenger2"/><ref name="Janzen"/>

==Colour== The dorsal body colour of ''F. asperrima'' is olive brown. The anterior half of the body has 20–32 distinct large black spots or cross bars. The posterior body may lack them or may be in light-colored irregular shapes. The head is dark in color. Two black lines run diagonally from behind the eyes to the corners of the mouth. Ventrally, the body is white. ''F. asperrimus'' can be easily identified by dark spots or bars on the first half of the body and two dark lines behind the eyes.<ref name="Boulenger"/><ref name="Suranjan"/>

==Behaviour== ''F. asperrima'' is oviparous, diurnal and nocturnal.{{Dubious|date=July 2014}} In dry conditions during the summer, it undergoes aestivation. It is active in water bodies in search of its prey, which consist mainly of fishes and frogs. It is known to be very aggressive. When threatened, it attempts to bite, by flattening its head and neck as does the cobra. The bite may cause wounds. Also, it may release a noxious odor.<ref name="Boulenger"/><ref name="Suranjan"/>

==Breeding== The gestation period of ''F. asperrima'' is 55–67 days. Females do not guard the clutches of eggs, but they stay close to the nest. They lay clutches of four to 30 eggs between September and October.<ref name="Boulenger"/><ref name="Suranjan"/><ref name="Boulenger2"/>

==Common names== *English: Boulenger's keelback or Sri Lankan keelback *Sinhalese: දිය බරියා/දිය නයා<ref name="Suranjan"/><ref name="silva"/>

==References== {{Reflist|30em|refs= <ref name="JHU">{{cite book |last1=Beolens |first1=Bo |author-link=Richard Allen "Bo" Crombet-Beolens|last2=Watkins |first2=Michael |last3=Grayson |first3=Michael|title=The Eponym Dictionary of Reptiles|year=2011 |publisher = Johns Hopkins University Press|pages=33–35 |isbn=978-1-4214-0135-5 |lccn=1421401355|name-list-style=amp}}</ref>

<ref name="Boulenger">{{cite journal |last1=Boulenger|first1=G.A.|author-link=George Albert Boulenger|title=Description of new oriental reptiles and batrachians |url=https://www.biodiversitylibrary.org/bibliography/15774|journal=Annals and Magazine of Natural History |volume=6 |year=1891 |publisher=Taylor and Francis, Ltd. London|pages=279–283}}</ref> <ref name="Boulenger2">{{cite book |last1=Boulenger|first1=G.A.|title=Catalogue of the snakes in the British Museum.(Natural history) Vol. I |url=https://archive.org/stream/catalogueofsnake01brit#page/368/mode/2up |year=1893 |publisher=Taylor and Francis, London|pages=448}}</ref> <ref name="das">{{cite book |last1=Das|first1=I.|author-link1=:fr:Indraneil Das|last2=De Silva|first2=A.|title=Photographic guide to snakes and other reptiles of Sri Lanka |year=2005 |publisher=New Holland Publishers|pages=144|name-list-style=amp}}</ref> <ref name="silva">{{cite book |last1=De Silva|first1=A.|title=Snakes of Sri Lanka: a checklist and an annotated bibliography |year=1998 |publisher=Dept. Wildlife Conservation/GEF/UNDP/FAO, Colombo }}</ref> <ref name="Smith">{{cite book |last1=Smith|first1=M.A.|author-link=Malcolm Arthur Smith|title=The Fauna of British India, Ceylon and Burma, Including the Whole of the Indo-Chinese Sub-Region. Reptilia and Amphibia |url=https://www.biodiversitylibrary.org/bibliography/15774 |chapter=3. Serpentes|year=1943 |publisher=Taylor and Francis, Ltd. London|pages=583}}</ref> <ref name="Suranjan">{{cite journal |last1=Suranjan Karunarathna|first1=D. M. S.|last2=Thasun Amarasinghe|first2=A. A.|title=A Preliminary Survey of the Reptile Fauna in Nilgala Forest and its Vicinity, Monaragala District, Sri Lanka |year=2011 |journal=Taprobanica |volume=3 |issue=2 |pages=69–76|doi=10.47605/tapro.v3i2.49 |name-list-style=amp|doi-access=free}}</ref> <ref name="Edward">{{cite journal |last1=Taylor|first1=Edward H.|author-link=Edward Harrison Taylor|title=The snakes of Ceylon |year=1950 |url=http://biostor.org/reference/21244 |journal=University of Kansas Science Bulletin |volume=33 |issue=14 |pages=519–603|issn=0022-8850}}</ref> <ref name="Vogel">{{cite journal |last1=Vogel |first1=G. |last2=David |first2=Patrick |title=On the taxonomy of the ''Xenochrophis piscator'' complex (Serpentes, Natricidae) |year=2006 |journal=Herpetologia Bonnensis |volume=II |pages=241–246 |url=http://www.gernot-vogel.de/publications/On%20the%20taxonomy%20of%20the%20Xenochrophis%20piscator%20complex.pdf |name-list-style=amp }}</ref> <ref name="Wall">{{cite book |last1=Wall|first1=Frank|author-link=Frank Wall (herpetologist)|title=Ophidia Taprobanica or the Snakes of Ceylon |year=1921 |publisher=Colombo Mus. (H. R. Cottle, govt. printer), Colombo |pages=581}}</ref> <ref name="Janzen">{{cite journal |last1=Janzen|first1=P. |last2=Klaas|first2=P. |last3=Ziesmann|first3=S.|title=Sri Lankas Schlangenfauna |year=2007 |journal=Draco |volume=7 |issue=30 |pages=56–64 |name-list-style=amp}}</ref>}}

== External links == * [https://web.archive.org/web/20110513085615/http://www.arkive.org/boulengers-keelback/xenochrophis-asperrimus/ Boulenger's keelback (''Xenochrophis asperrimus'')] * [https://archive.today/20130210024752/http://zipcodezoo.com/Animals/X/Xenochrophis_asperrimus/ ''Xenochrophis asperrimus'' (Boulenger's keelback)]

Category:Fowlea Category:Endemic reptiles of Sri Lanka Category:Reptiles described in 1891 Category:Taxa named by George Albert Boulenger