INFRAORDER SCOLECOPHIDIA - BLIND SNAKES
Six Paraguayan species in this Infraorder are shared between three families. The families are separable largely on the basis of arrangement of head scales, skeletal morphology and dental arrangement. All have the following characteristics in common:
1 A cylindrical body with the head undifferentiated from the body.
2 A spine at the tip of the tail (large in Typhlopidae, small in other families).
3 Eyes covered by scales, sometimes visible, sometimes absent.
4 Dorsal and ventral scales small, smooth and of approximately equal size.
FAMILY ANOMALEPIDIDAE - SLENDER BLIND SNAKES
Two Paraguayan species in the genus Liotyphlops. They have a transverse maxilla that is movable and toothed. Dentary has 1 or 2 teeth. Tracheal lung is present and right lung is elongate. Left lung is vestigial or absent. Ectopterygoid bone present and articulates with the maxilla. Circumorbital bones are also present. Nasal glands exposed and not covered by frontal. No vestige of pelvic girdle. Oviducts paired or, in some cases the left is vestigial or absent. Oviparous.
Characteristics of the Paraguayan members of the genus Liotyphlops
A large rostral scale is in contact with the frontal, which prevents the prefrontals from contacting each other. Three or less scales contacting posterior edge of prefrontal. Two scales contacting posterior edge of nasal between second supralabial and prefrontal. Nasal scale in contact with second supralabial. There are no enlarged ventral scutes. The body is completely covered with smooth, cycloid scales. The rows of scales around the body show reduction patterns from anterior to posterior. The number of dorsals varies from 384 to 510. The total length varies from 88 to 413 mm. The eye spot is present or absent.
FAMILY LEPTOTYPHLOPIDAE - THREADSNAKES
Three Paraguayan species in two genera Epictia and Rena, all formerly placed in the larger genus Leptotyphlops. Maxilla in normal, longitudinal position. Teeth are present on the dentary only, none on the maxilla or any upper jaw element. Maxilla and upper jaw bones are immovable. Mandibular bones movably articulated. Pelvic girdle is vestigial. No tracheal lung, the right lung is developed and there is no vestige of a left lung. Female has a right oviduct only. Oviparous.
FAMILY TYPHLOPIDAE - BLIND SNAKES
One species in the genus Amerotyphlops. They have a transverse maxilla that is movable and toothed. Dentary is toothless, only the maxillary bears teeth. Tracheal lung is present and right lung is elongate. Left lung is vestigial or absent. No ectopterygoid bone or circumorbital bones present. Nasal and pre-frontal bones fused. Nasal gland covered by pre-frontal. Vestigial pelvic girdle present internally. Oviparous.
Key to Adults of Paraguayan Blind Snakes
Illustrations (not to scale) of the head scale patterns of all Paraguayan species are provided as an aid to identification via the key, with the note that such scale patterns are sometimes variable. The illustrations alone should not be relied on for identification, and should be used only to confirm a keyed identification.
1a Rostral scale somewhat pointed, so that when viewed laterally the head appears to be "beaked" ..................................................................................................................................................... Rena unguirostris
1b Rostral scale with rounded profile when viewed laterally............................................................................ 2
2a Rostral scale greatly enlarged when viewed dorsally, bordered on each side by up to three lateral scales and posteriorly by one long frontal scale that is at least twice as wide as it is long. ................................ Liotyphlops 3
2b Rostral scale bordered laterally by only one large scale on each side, and posteriorly by a single small frontal scale that is approximately as wide as it is long. ................................................................................................. 4
3a Mid body scale rows 20. Posterior body scale rows 20. Dorsal scales less than 463 (384 to 455) ...................................................................................................................................................... Liotyphlops beui
3b Mid body scale rows usually 22. Posterior body scale rows 22. Dorsal scales more than 463 (463 to 510) ................................................................................................................................................ Liotyphlops ternetzii
4a In dorsal view the three scales in contact posteriorly with the frontal are of approximately equal size. Tendency for nasal and prefrontal to be fused in lateral view. ....................................Amerotyphlops brongersmianus
4b In dorsal view the three scales in contact posteriorly with the frontal are of unequal size. Nasal and prefrontal not fused in lateral view. ........................................................................................................ Epictia 5
5a Ten scale rows around the tail. Colour pattern with pale ground colour and darker longitudinal lines. Supraocular not in contact with first supralabial. No black caudal ring. Between 190 to 230 scale rows along the body. .............................................................................................................................................. Epictia munoai
5b Twelve scale rows around the tail. Colour pattern with dark ground colour and deeply pigmented longitudinal stripes and moderate dorsoventral contrast. Supraocular subequal to ocular in dorsal view. Posterior rostral border at a level anterior to the eye. Lower eye border higher than nasal suture. Between 213-231 scale rows along the body. ............................................................................................................... Epictia albipuncta
REFERENCES
Cei JM 1993 - Reptiles del Noroeste, Nordeste y Este de la Argentina: Herpetofauna de las Selvas Subtropicales, Puna y Pampas - Museo Regionale di Scienze Naturali Monografie XIV, Torino.
Dixon JR, Kofron CP 1983 - The Central and South American Anomalepid Snakes of the Genus Liotyphlops - Amphibia-Reptilia 4: p241-264.
Fouquette MJ (unpublished) - Synopsis of Recent Reptiles to Genus - Arizona University
Peters JA, Orejas-Miranda B 1986 - Catalogue of the Neotropical Squamata Part 1: Snakes - Smithsonian Institution Press, Washington.
Whitfield P Ed.1984 - Longman Illustrated Animal Encyclopedia - Guild Publishing, London.
Six Paraguayan species in this Infraorder are shared between three families. The families are separable largely on the basis of arrangement of head scales, skeletal morphology and dental arrangement. All have the following characteristics in common:
1 A cylindrical body with the head undifferentiated from the body.
2 A spine at the tip of the tail (large in Typhlopidae, small in other families).
3 Eyes covered by scales, sometimes visible, sometimes absent.
4 Dorsal and ventral scales small, smooth and of approximately equal size.
FAMILY ANOMALEPIDIDAE - SLENDER BLIND SNAKES
Two Paraguayan species in the genus Liotyphlops. They have a transverse maxilla that is movable and toothed. Dentary has 1 or 2 teeth. Tracheal lung is present and right lung is elongate. Left lung is vestigial or absent. Ectopterygoid bone present and articulates with the maxilla. Circumorbital bones are also present. Nasal glands exposed and not covered by frontal. No vestige of pelvic girdle. Oviducts paired or, in some cases the left is vestigial or absent. Oviparous.
Characteristics of the Paraguayan members of the genus Liotyphlops
A large rostral scale is in contact with the frontal, which prevents the prefrontals from contacting each other. Three or less scales contacting posterior edge of prefrontal. Two scales contacting posterior edge of nasal between second supralabial and prefrontal. Nasal scale in contact with second supralabial. There are no enlarged ventral scutes. The body is completely covered with smooth, cycloid scales. The rows of scales around the body show reduction patterns from anterior to posterior. The number of dorsals varies from 384 to 510. The total length varies from 88 to 413 mm. The eye spot is present or absent.
FAMILY LEPTOTYPHLOPIDAE - THREADSNAKES
Three Paraguayan species in two genera Epictia and Rena, all formerly placed in the larger genus Leptotyphlops. Maxilla in normal, longitudinal position. Teeth are present on the dentary only, none on the maxilla or any upper jaw element. Maxilla and upper jaw bones are immovable. Mandibular bones movably articulated. Pelvic girdle is vestigial. No tracheal lung, the right lung is developed and there is no vestige of a left lung. Female has a right oviduct only. Oviparous.
FAMILY TYPHLOPIDAE - BLIND SNAKES
One species in the genus Amerotyphlops. They have a transverse maxilla that is movable and toothed. Dentary is toothless, only the maxillary bears teeth. Tracheal lung is present and right lung is elongate. Left lung is vestigial or absent. No ectopterygoid bone or circumorbital bones present. Nasal and pre-frontal bones fused. Nasal gland covered by pre-frontal. Vestigial pelvic girdle present internally. Oviparous.
Key to Adults of Paraguayan Blind Snakes
Illustrations (not to scale) of the head scale patterns of all Paraguayan species are provided as an aid to identification via the key, with the note that such scale patterns are sometimes variable. The illustrations alone should not be relied on for identification, and should be used only to confirm a keyed identification.
1a Rostral scale somewhat pointed, so that when viewed laterally the head appears to be "beaked" ..................................................................................................................................................... Rena unguirostris
1b Rostral scale with rounded profile when viewed laterally............................................................................ 2
2a Rostral scale greatly enlarged when viewed dorsally, bordered on each side by up to three lateral scales and posteriorly by one long frontal scale that is at least twice as wide as it is long. ................................ Liotyphlops 3
2b Rostral scale bordered laterally by only one large scale on each side, and posteriorly by a single small frontal scale that is approximately as wide as it is long. ................................................................................................. 4
3a Mid body scale rows 20. Posterior body scale rows 20. Dorsal scales less than 463 (384 to 455) ...................................................................................................................................................... Liotyphlops beui
3b Mid body scale rows usually 22. Posterior body scale rows 22. Dorsal scales more than 463 (463 to 510) ................................................................................................................................................ Liotyphlops ternetzii
4a In dorsal view the three scales in contact posteriorly with the frontal are of approximately equal size. Tendency for nasal and prefrontal to be fused in lateral view. ....................................Amerotyphlops brongersmianus
4b In dorsal view the three scales in contact posteriorly with the frontal are of unequal size. Nasal and prefrontal not fused in lateral view. ........................................................................................................ Epictia 5
5a Ten scale rows around the tail. Colour pattern with pale ground colour and darker longitudinal lines. Supraocular not in contact with first supralabial. No black caudal ring. Between 190 to 230 scale rows along the body. .............................................................................................................................................. Epictia munoai
5b Twelve scale rows around the tail. Colour pattern with dark ground colour and deeply pigmented longitudinal stripes and moderate dorsoventral contrast. Supraocular subequal to ocular in dorsal view. Posterior rostral border at a level anterior to the eye. Lower eye border higher than nasal suture. Between 213-231 scale rows along the body. ............................................................................................................... Epictia albipuncta
REFERENCES
Cei JM 1993 - Reptiles del Noroeste, Nordeste y Este de la Argentina: Herpetofauna de las Selvas Subtropicales, Puna y Pampas - Museo Regionale di Scienze Naturali Monografie XIV, Torino.
Dixon JR, Kofron CP 1983 - The Central and South American Anomalepid Snakes of the Genus Liotyphlops - Amphibia-Reptilia 4: p241-264.
Fouquette MJ (unpublished) - Synopsis of Recent Reptiles to Genus - Arizona University
Peters JA, Orejas-Miranda B 1986 - Catalogue of the Neotropical Squamata Part 1: Snakes - Smithsonian Institution Press, Washington.
Whitfield P Ed.1984 - Longman Illustrated Animal Encyclopedia - Guild Publishing, London.
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