Iberian worm lizard

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Iberian worm lizard
Iberian worm lizard.jpg
Two Iberian worm lizards
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Family: Blanidae
Genus: Blanus
Species:
B. cinereus
Binomial name
Blanus cinereus
(Vandelli, 1797)
Blanus cinereus distribution Map.png
Synonyms
  • Amphisbæna cinereaVandelli, 1797
  • Blanus cinereus— Wagler, 1865 [2]
An Iberian worm lizard Culebra Ciega - panoramio.jpg
An Iberian worm lizard
B. cinereus with a human finger for scale Culebra ciega.jpg
B. cinereus with a human finger for scale

The Iberian worm lizard, Mediterranean worm lizard, or European worm lizard (Blanus cinereus) is a species of reptile in the family Blanidae (worm lizards) of the clade Amphisbaenia. The Iberian worm lizard is locally known as cobra-cega (Portuguese), culebrilla ciega (Spanish), and colobreta cega (Catalan), [3] all meaning "blind snake". Recent studies into the mitochondrial and nuclear genomic data of 47 isolated B. cinereus populations show rather large sequence divergence between two apparent clades, leading some researchers to call for a division of the Iberian worm lizard into two species. [4] While little is known of B. cinereus in comparison with some other reptile species, new insight is growing about this primitive, ancestral reptile.

Contents

Geographic range

The Iberian worm lizard is found within Portugal and through most of central and southern Spain.

Habitat

B. cinereus is a subterranean species found in a wide variety of Mediterranean habitats. Their abundance in population in different regions is difficult to determine due to their subterranean nature. However, studies on B. cinereus activity have shown the organism's ability to survive in habitats between 400 meters and 1400 meters. [5] The Iberian worm lizard is a thermoregulator meaning it can only survive in habitats conducive to its thermoregulatory needs. [6] Typical habitats for B. cinereus consist of areas of high humus and sporadic rocks of varying thickness. B. cinereus will take advantage of their habitat's loose soil depth and rocks as means for thermoregulation. Depending on the time of day Iberian worm lizards will move in between 0 cm and 10 cm of soil and underneath rocks varying in thickness from 10 cm to 20 cm. B. cinereus will use the depth of soil, particularly the deeper soil, to cool down and the rocks to warm itself to varying degrees based on the time of day and thickness of the rocks. By using its habitat, the Iberian worm lizard is able to maintain a constant body temperature with minimal energy expense. [7]

Diet

The Iberian worm lizard is believed to be an opportunistic feeder through the study of central Spanish B. cinereus populations. Initially, B. cinereus was thought to feed on the diverse array of prey that inhabited the underside of rocks, but a correlation with feeding habits and under rock prey was not seen. Its diet consisting mainly of insects and insect larvae, which are the worm lizard's most abundant food source, led observers to make the conclusion that B. cinereus acts as an opportunistic feeder. While being an overall opportunistic feeder, B. cinereus will instinctively hunt for larger insect larvae and will refrain from eating certain ant species, thus showing a level of prey distinguishing during opportunistic feeding. B. cinereus is also believed to have low energy requirements based on average stomach content in comparison with other lizard species. It is speculated that Iberian worm lizards will search for scarce but energy-rich foods when habitats allow for this type of feeding, but can adapt and feed on abundant and less energy-rich prey when necessary. [8]

Morphology

The Iberian worm lizard has similar morphology to a worm because of its limbless ringed body, but unlike worms it possesses small, underdeveloped eyes, small smooth scales, and most importantly it has all characteristics of a typical vertebrate like, vertebral column, lungs, and closed circulatory system. The head is small and blunt, used for digging, with underdeveloped eyes covered by skin, and a characteristically ridged ringed body covered in scales. Iberian worm lizard tails are short and possess the same scales. It has a small forked tongue used for chemosensory signaling purposes, and a row of small but sharp teeth within the mouth's interior. Its coloration is fleshy-pink, violet, or brown depending on its region. Adults are usually about 150 mm (5.9 in) in total length, but can be up to 300 mm (12 in) in total length. Iberian worm lizards are frequently mistaken for small snakes or large worms. [9]

Chemosensory signaling

Due to its subterranean lifestyle, the Iberian worm lizard exhibits characteristically small, primitive eyes. These eyes leave the B. cinereus with almost a complete inability to see, only distinguishing changes in light intensity. However, B. cinereus has made up for its lack of sight through the development of a chemosensory signaling systems. Chemosensory signaling is mediated by the extremely sensitive vomeronasal organ on the head of the B. cinereus. The response to individual chemical stimuli can be measured by counting tongue flicks. [10]

Prey signaling

Cotton swabs exhibiting prey specific chemical indicators elicit tongue flick responses by the B. cinereus. However, there is no difference in this response between prey and non-prey signals. In contrast, tests with live prey instead of cotton swabs have shown that B. cinereus can clearly discriminate between live prey and live non-prey based on the chemicals given off by the individuals. A consistent and direct correlation has been seen in testing between higher average of tongue flicks in the presence of live prey than in the presence of non-live prey. The distinction between cotton swab and live prey testing suggests the ability of B. cinereus to distinguish live prey and non-prey chemical signals. [10]

Predator signaling

Cotton swab studies emitting predatory chemosensory signals have also been performed in order to quantify the Iberian worm lizard's anti-predatory response mechanisms. Swabs exhibiting signals from predators like the southern smooth snake, Coronella girondica , the scolopendromorph centipede (Scolopendra), and the Bedriaga's skink, Chalcides bedriagai were all tested. Again, the amount and rate of tongue flicks was used to quantify the anti-predatory response, as well as any defensive acts taken upon the swab. High rates of tongue flicks were seen for all three predator chemicals with defensive biting by B. cinereus subjects on the swabs smelling like snake or centipede. While a conclusive statement cannot be made about the hierarchy of predators based on tongue flicks, the self-defense response would indicate the skink as being the greatest threat to B. cinereus. [11]

Habitat signaling

Evidence has also been seen for a chemosensory signaling response between the Iberian worm lizard and its environment. This phenomenon has been seen in the time it takes for the anti-predatory response of burrowing into the soil in familiar and unfamiliar locations. A delay is seen in the burrowing of B. cinereus upon predatory signaling in an unfamiliar location, but as soon as the B. cinereus is returned to its familiar habitat its burrowing response is greatly increased. [12] Precloacal secretions from males and females include long chain waxy-type esters of carboxylic acids that are thought to be secreted along tunnels to help multiple Iberian worm lizards find their way. [13]

Sex differentiation signaling

Chemosensory signaling is especially important in sex-distinction between Iberian worm lizards. The pheromones released from the precloacal glands of the male and female are sex specific in composition. The secretions from these precloacal glands have been isolated and its contents identified for both male and female. The compound squalene is secreted in high concentrations from males, while tocopherol is specific for female secretions. [13] The role of squalene in male secretions has been proved to be enough for a male recognition, while tocopherol is only suspected to be based on its high concentrations in female excretions and not males. [14]

Phylogeny

Very little is known about the origins of amphisbaenians, and even less for the Iberian worm lizard. Phylogenetic analysis of two nuclear genes from the tissue of a modern amphisbaena specimen and that from museum fossil samples has shed some light on the origins of amphisbaena. The data would suggest a widespread convergence of limb loss as well as skull morphology from Rhineuridae and Bipedidae lineages. DNA analysis would suggest that there were three separate incidences of limb loss all convergent for amphisbaena formation. [15] This evidence, as well as a look into mitochondrial and genomic DNA of B. cinereus has led some experts to believe there ought to be two distinct taxonomic clades within B. cinereus located on the Iberian peninsula. While morphological characteristics are less defined between the two proposed clades, the genetic variation is incontrovertible and significant enough to make gene flow unlikely. Experts attribute these divergent potential clades, and their potential to continue to differentiate, to constraints of subterranean life. The clades are distinguished based on their locations with B. cinereus being located centrally on the peninsula and the second proposed clade Blanus mariae located on the southwestern side of the Iberian peninsula. [16]

Related Research Articles

<span class="mw-page-title-main">Lizard</span> Informal group of reptiles

Lizards are a widespread group of squamate reptiles, with over 7,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The group is paraphyletic since it excludes the snakes and Amphisbaenia although some lizards are more closely related to these two excluded groups than they are to other lizards. Lizards range in size from chameleons and geckos a few centimeters long to the 3-meter-long Komodo dragon.

<span class="mw-page-title-main">Lepidosauria</span> Superorder of reptiles

The Lepidosauria is a subclass or superorder of reptiles, containing the orders Squamata and Rhynchocephalia. Squamata includes snakes, lizards, and amphisbaenians. Squamata contains over 9,000 species, making it by far the most species-rich and diverse order of reptiles in the present day. Rhynchocephalia was a formerly widespread and diverse group of reptiles in the Mesozoic Era. However, it is represented by only one living species: the tuatara, a superficially lizard-like reptile native to New Zealand.

<span class="mw-page-title-main">Amphisbaenia</span> Suborder of reptiles

Amphisbaenia is a group of usually legless squamates, comprising over 200 extant species. Amphisbaenians are characterized by their long bodies, the reduction or loss of the limbs, and rudimentary eyes. As many species have a pink body and scales arranged in rings, they have a superficial resemblance to earthworms. While the genus Bipes retains forelimbs, all other genera are limbless. Although superficially similar to the snakes, legless lizards, and blind lizards, recent phylogenetic studies suggest that they are most closely related to wall lizards of the family Lacertidae. Amphisbaenians are widely distributed, occurring in North America, Europe, Africa, South America, Western Asia and the Caribbean. Most species are less than 6 inches (15 cm) long.

<span class="mw-page-title-main">Amphisbaenidae</span> Family of amphisbaenians

The Amphisbaenidae are a family of amphisbaenians, a group of limbless vertebrates.

<i>Podarcis hispanicus</i> Species of lizard

Podarcis hispanicus, also known as Iberian wall lizard, is a small wall lizard species of the genus Podarcis. It is found in the Iberian peninsula, in northwestern Africa and in coastal districts in Languedoc-Roussillon in France. In Spanish, this lizard is commonly called lagartija Ibérica.

<i>Iberolacerta cyreni</i> Species of lizard

Iberolacerta cyreni, commonly known as the Cyren's rock lizard, is a species of lizard in the family Lacertidae. The species is endemic to central Spain and is currently listed as endangered by the IUCN due to global warming. I. cyreni has evolved to exhibit key behavioral characteristics, namely individual recognition, in which a lizard is able to identify another organism of the same species, as well as thermoregulation.

<i>Blanus</i> Genus of amphisbaenians

Blanus is a genus of amphisbaenians found in the Mediterranean region of Europe and North Africa. Like other amphisbaenians, Blanus species are specialized for a subterranean existence, with long, slender bodies, reduced limbs, and rudimentary eyes. Their skulls are powerfully constructed, allowing them to push through soil to create a burrow. Their jaws are well-developed, with large, recurved teeth and a pair of canine-like teeth in the upper jaw.

<span class="mw-page-title-main">Moroccan worm lizard</span> Species of amphisbaenian

The Moroccan worm lizard is a species of amphisbaenian in the family Blanidae. The species is endemic to Morocco.

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<i>Liolaemus chiliensis</i> Species of reptile

Liolaemus chiliensis is a species of lizard in the family Liolaemidae, also referred to as the weeping or crying lizard in English. Synonyms for this species include Liodeira chilensis and Calotes chiliensis. Less commonly, it is called the Talcahuano Smooth-throated Lizard.

<span class="mw-page-title-main">Bipedidae</span> Family of amphisbaenians

Bipedidae is a family of amphisbaenians that includes the extant genus Bipes represented by three species from Baja California and the southern coast of Mexico and the extinct genus Anniealexandria represented by one species that lived in what is now Wyoming during the earliest Eocene around 55 million years ago. Phylogenetic analysis indicates that Bipedidae is most closely related to the family Blanidae, which includes the living genus Blanus.

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The Lindi sharp-snouted worm lizard, also known commonly as Barker's sharp-snouted worm lizard, is a species of amphisbaenian in the family Amphisbaenidae. The species is endemic to Tanzania. There are two recognized subspecies.

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<span class="mw-page-title-main">Turkish worm lizard</span> Species of amphisbaenian

The Turkish worm lizard is a species of amphisbaenian in the family Blanidae. The species is native to Southeast Europe and the Middle East. There are two recognized subspecies.

References

  1. ↑ Juan M. Pleguezuelos, Paulo Sá-Sousa, Valentin Pérez-Mellado, Rafael Marquez, Iñigo Martínez-Solano (2009). "Blanus cinereus". IUCN Red List of Threatened Species . 2009: e.T61469A12490902. doi: 10.2305/IUCN.UK.2009.RLTS.T61469A12490902.en . Retrieved 16 November 2021.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  2. ↑ Boulenger, G.A. 1885. Catalogue of the Lizards in the British Museum (Natural History). Second Edition. Volume II. ...Amphisbænidæ. Trustees of the British Museum (Natural History). (Taylor and Francis, Printers.) xiii + 497 pp. + Plates I.- XXIV. (Blanus cinereus, pp. 433-434.)
  3. ↑ el País Valencià - Espais naturals protegits Archived 2009-08-22 at the Wayback Machine
  4. ↑ Albert, E. M., R. Zardoya, and M. García-París. "Phylogeographical and Speciation Patterns in Subterranean Worm Lizards of the Genus Blanus (Amphisbaenia: Blanidae)." Molecular Ecology 16.7 (2007): 1519-531. Print.
  5. ↑ Salavador, Alfredo, and Pilar Lopez. "Microhabitat Selection of the Amphisbaenian Blanus Cinereus." Copeia. By Jose Martin. 4th ed. Vol. 1991. N.p.: American Society of Ichthyologists and Herpetologists (ASIH), n.d. 1142-146. Print.
  6. ↑ "Thermoregulator".
  7. ↑ Lopez, Pilar, Alfredo Salvador, and Jose Martin. "Soil Temperature, Rock Selection, and the Thermal Ecology of the Amphisbaenian Reptile Blanus Cinereus." Canadian Journal of Zoology 76.4 (1988): 693-97. Print.
  8. ↑ Martin, Jose, and Alfredo Salvador. "Diet Selection by the Amphisbaenian Blanus Cinereus." Herpetologica. By Pilar López. 2nd ed. Vol. 47. N.p.: Herpetologists' League, n.d. 210-18. Print.
  9. ↑ "Servicio desactivado".[ permanent dead link ]
  10. 1 2 Lopez, Pilar, and Alfredo Salvador. "Tongue-Flicking Prior to Prey Attack by the Amphisbaenian Blanus Cinereus." Journal of Herpetology 28.4 (1994): 502-04. Print.
  11. ↑ López, Pilar, and Jose Martı́n. "Chemosensory Predator Recognition Induces Specific Defensive Behaviours in a Fossorial Amphisbaenian." Animal Behaviour 62.2 (2001): 259-64. Print.
  12. ↑ Martin, Jose, Pilar López, and Andres Barbosa. "Site Familiarity Affects Antipredator Behavior of the Amphisbaenian Blanus Cinereus." Canadian Journal of Zoology 78.12 (2000): 2142-146. Print.
  13. 1 2 López, Pilar, and José Martín. "Intersexual Differences in Chemical Composition of Precloacal Gland Secretions of the Amphisbaenian Blanus Cinereus." Journal of Chemical Ecology 31.12 (2005): 2913-921. Print.
  14. ↑ Lopez, P., and J. Martin. "Potential Chemosignals Associated with Male Identity in the Amphisbaenian Blanus Cinereus." Chemical Senses 34.6 (2009): 479-86. Print.
  15. ↑ Kearney, Maureen, and Bryan L. Stuart. "Repeated Evolution of Limblessness and Digging Heads in Worm Lizards Revealed by DNA from Old Bones."Proceedings of the Royal Society B: Biological Sciences 271.1549 (2004): 1677-683. Print.
  16. ↑ "Evidence of Cryptic Speciation in a Fossorial Reptile: Description of a New Species of Blanus (Squamata: Amphisbaenia: Blanidae) from the Iberian Peninsula." Zootaxa 2234 (2009): 54-56.http://webext.ebd.csic.es:8080/documents/12813/16940/eva_Albert.pdf. Web. 8 Oct. 2013.

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