22 chapters
28 minute read
Selected Chapters
22 chapters
Morphological Variation in a Population of the Snake, Tantilla gracilis Baird and Girard
Morphological Variation in a Population of the Snake, Tantilla gracilis Baird and Girard
BY LAURENCE M. HARDY AND CHARLES J. COLE University of Kansas Lawrence 1968 University of Kansas Publications, Museum of Natural History Editors: E. Raymond Hall, Chairman, Frank B. Cross, Henry S. Fitch, J. Knox Jones, Jr. Volume 17, No. 15, pp. 613-629, 6 figs. Published May 14, 1968 University of Kansas Lawrence, Kansas PRINTED BY ROBERT R. (BOB) SANDERS, STATE PRINTER TOPEKA, KANSAS 1968 31-9422 Morphological Variation in a Population of the Snake, Tantilla gracilis Baird and Girard By LAURE
1 minute read
Read Chapter
Read Chapter
Materials and Methods
Materials and Methods
The specimens examined were donated to the Museum of Natural History, University of Kansas, by the late Paul Anderson of Independence, Missouri. All specimens (KU numbers 83435-83680; N = 246) were collected in the vicinity of Winfield, Cowley County, Kansas, by Charles E. Burt and students from Southwestern College in the period from 1938 to 1941, inclusive. Both authors gathered data on most characteristics and examined each atypical individual. Hardy determined characters of the maxillae (whi
3 minute read
Read Chapter
Read Chapter
General Characteristics
General Characteristics
From the data given by Force (1935), Taylor (1936), and Kirn et al. (1949), and from our own data, we conclude that a typical specimen of gracilis , meaning a specimen having the usual characteristics of the species, has the following characteristics in combination: supralabials 6-6; infralabials 6-6; preoculars 1-1; postoculars 1-1; temporals 1 + 1 on each side; nasal divided below naris; supralabials 3 + 4 entering orbit; mental in contact with chin-shields; all five dorsal scale counts 15; an
44 minute read
Read Chapter
Read Chapter
Sex
Sex
The sample (N = 246) is composed of 107 (43.5%) females and 139 (56.5%) males....
4 minute read
Read Chapter
Read Chapter
Measurements
Measurements
Females have total lengths from 96 to 244 mm. (mean, 173.3; N = 79). One female (KU 83480) measuring 244 mm. may be the longest specimen known (Conant, 1958, reports the longest as 9-1/8 inches—approximately 232 mm.). Males have total lengths from 96 to 215 mm. (mean, 162.4; N = 109). Females have tail lengths from 16 to 50 mm. (mean, 34.6; N = 79), and males have tail lengths from 21 to 53 mm. (mean, 37.8; N = 109). The ratio of tail length to total length in females is from 0.17 to 0.22 (mean,
1 minute read
Read Chapter
Read Chapter
Supralabials
Supralabials
The supralabials are either six (usually) or seven on a side ( Table 1 ). When seven supralabials are present on either one or both sides, the addition results from one of the following conditions: a) 5 is divided to form 5 and 6 (N = 6); b) 2 and 3 form 2, 3, and 4 (N = 1); c) 5 and 6 form 5, 6, and 7 (N = 12); d) 4, 5, and 6 form 4, 5, 6, and 7 (N = 1); e) 1 and 2 form 1, 2, and 3 (N = 1); f) 1, 2, and 3 form 1, 2, 3, and 4 (N = 1); g) 2 is fused with the nasal, and 3 and 4 are reduced to gran
1 minute read
Read Chapter
Read Chapter
Infralabials
Infralabials
The infralabials are five, six (usually), or seven on a side ( Table 1 ). When five infralabials are present on either one or both sides, the reduction results from one of the following conditions: a) 2 and 3 are fused (N = 3); b) 1, 2, and 3 form 1 and 2 (N = 6); c) 2, 3, and 4 form 2 and 3 (N = 3); d) 5 is separated from the edge of the lip by a projection from an adjacent infralabial (N = 1); e) 1, 2, 3, and 4 form 1, 2, and 3 (N = 2); f) type of reduction unknown (N = 4). Of the specimens wi
1 minute read
Read Chapter
Read Chapter
Preoculars
Preoculars
Of the 245 specimens examined, 242 (98.8%) have one preocular on each side. Both preoculars are absent from two specimens, and one specimen has 1-0. In each case when a preocular is lacking, the "preocular" and prefrontal are fused. One specimen having 1-1 preoculars has both of them reduced to small vertical slivers....
15 minute read
Read Chapter
Read Chapter
Postoculars
Postoculars
Of the 245 specimens examined, 242 (98.8%) have one postocular on each side. Postoculars are 2-1 in two specimens and 1-2 in one. In one specimen the lower of the two postoculars on each side is very small, being approximately 1/6 the diameter of the upper one (measured with an ocular micrometer)....
15 minute read
Read Chapter
Read Chapter
Temporals
Temporals
Of the 245 specimens examined, 235 (95.9%) have 1 + 1 temporals on each side. Four specimens exhibit addition of temporals: one specimen has two secondary temporals on the left, and one has a tertiary temporal on the left. Two specimens have partly healed head injuries that probably caused atypical temporal conditions: one specimen has two primary temporals on the left, and one has two secondary temporals on the left and two upper and one lower secondary temporal on the right. Six specimens exhi
1 minute read
Read Chapter
Read Chapter
Nasal
Nasal
Of the 243 specimens examined, 237 (97.5%) have the nasal divided below the naris on both sides. Three specimens have the nasal completely divided (above and below the naris) on only the left side; one specimen has a completely divided nasal on only the right side. A groove, but not a complete division of the nasal, is present above the left naris of one specimen. One specimen lacks the typical division below the naris on both sides, but a complete suture is present posterior to the naris and th
27 minute read
Read Chapter
Read Chapter
Contact of prefrontal with supralabials
Contact of prefrontal with supralabials
Of the 243 specimens examined, 147 (60.5%) have the prefrontal separated from the labials on each side. Of the remaining 96 specimens, 53 (21.8% of the 243) have the prefrontals in contact with the second labial on each side; five other variations of this characteristic were observed ( Table 2 ). Table 2. Variation in Contact of the Prefrontals and the Labials in 243 Specimens of Tantilla gracilis. The specimen having the prefrontal in contact with labial 2 on the left and labial 3 on the right
1 minute read
Read Chapter
Read Chapter
Supralabials entering orbit
Supralabials entering orbit
Of the 246 specimens examined, 233 (94.7%) have the third and fourth supralabials entering each eye ( Table 3 ). All snakes that have the fourth and fifth labials entering the orbit on either side also have seven supralabials on the same side. One specimen having only the fourth labial entering the eye on the right side also has six supralabials on that side, but the third supralabial is split diagonally and the part contacting the eye does not contact the lip and hence is not a supralabial. The
34 minute read
Read Chapter
Read Chapter
Contact of mental with chin-shields
Contact of mental with chin-shields
Of the 246 specimens examined, 190 (77.2%) have the mental in contact with both anterior chin-shields. The mental is in contact with only the left anterior chin-shield in 15 specimens, only the right anterior chin-shield in 2 specimens, and the mental does not contact either anterior chin-shield in 39 specimens. Separation of the mental and an anterior chin-shield always results from the posterior elongation of a first infralabial. Table 3 . Variation in Number of Supralabials Entering the Eye i
51 minute read
Read Chapter
Read Chapter
Dorsal scale rows
Dorsal scale rows
Of the 245 specimens examined for this characteristic, 228 (92.7%) have scale counts of 15-15-15-15-15. The number of scale rows around the neck and one head length behind the head are 15 except in a single specimen that has 14 scale rows at these three places. The number of scale rows around midbody is 15 in 244 of 246 specimens (99.2%); two specimens have 14 scale rows around midbody. The number of preanal scale rows is more variable; counts of 14 through 17 were recorded. Fourteen specimens h
1 minute read
Read Chapter
Read Chapter
Anal plate
Anal plate
Of the 246 specimens examined, 232 (94.3%) have the anal plate divided. Of the 14 specimens having undivided anal plates, four have an incomplete groove anteriorly in the plate....
8 minute read
Read Chapter
Read Chapter
Ventrals
Ventrals
Females have from 122 to 137 (mean, 130.8 ± 0.26; N = 107) ventrals; males have from 117 to 131 (mean, 122.3 ± 0.21; N = 139; Fig. 2 ). Of the 246 specimens examined, 29 (11.8%; 11 females and 18 males) have an added half-ventral immediately anterior to the anal plate. Of these specimens, 27 have the added half-ventral on the left side and two have it on the right. Five specimens have the last ventral divided similar to the normal division of the anal plate. One specimen has the last ventral inc
46 minute read
Read Chapter
Read Chapter
Subcaudals
Subcaudals
Females have from 37 to 47 (mean, 42.0 ± 0.20; N = 79) subcaudals; males have from 43 to 55 (mean, 48.4 ± 0.23; N = 109; Fig. 3 ). Of the 187 specimens examined, 13 (7.0%) have the last pair of subcaudals fused. One specimen has left subcaudal 28 fused with both adjacent subcaudals (also fused) on the right. While reading proof we found two omissions in Fig. 3 ; there should be illustrated two males with 43 subcaudals and three males with 44 subcaudals....
30 minute read
Read Chapter
Read Chapter
Ventrals minus subcaudals
Ventrals minus subcaudals
The value for number of ventrals minus the number of subcaudals varies from 80 to 96 (mean, 88.8 ± 0.39) for 79 females, and from 67 to 83 (mean, 73.8 ± 0.28) for 109 males....
10 minute read
Read Chapter
Read Chapter
Additional scale characteristics
Additional scale characteristics
Of the 246 specimens examined, four (1.6%) have the rostral in contact with the left prefrontal, and hence the internasals are separated from one another. One snake has approximately one-fourth (anteriorly) of the suture between the parietals fused. One specimen has the posterior edge of the frontal fused with the left parietal. One specimen has the parietal shield on the right side abbreviated posteriorly. One specimen has both prefrontals fused with the frontal, although an incomplete suture i
22 minute read
Read Chapter
Read Chapter
Maxillary characteristics (Figs. 4 and 5)
Maxillary characteristics (Figs. 4 and 5)
Maxillary teeth anterior to fangs 10-14 (mean, 12.1; N = 20); tooth-socket number 6.5-8.5 (mean, 7.2; N = 20) directly opposite distal tip of suborbital process; lateral anterior foramina 1-3 (mean, 1.8; N = 20); tooth number 6-9 (mean, 6.9; N = 12) directly below center of posterior foramen (if only two foramina present). Three specimens lack a diastema and 17 specimens have a diastema. The anterior and posterior edges of the suborbital process are parallel in two specimens and not parallel in
1 minute read
Read Chapter
Read Chapter
Discussion and Conclusions
Discussion and Conclusions
Generic characteristics of Tantilla are as follows: size small, body slender, head not noticeably distinct from body; preoculars one; postoculars one or two; nasals two; loreal absent; smooth dorsal scales in 15 rows; anal plate usually divided but sometimes single; subcaudals paired; usually two enlarged, posterior, grooved fangs on the maxilla separated by a small diastema from the other maxillary teeth (Baird and Girard, 1853:131; Cope, 1900:1110; Dunn, 1928:24; Blanchard, 1938:369; Schmidt a
9 minute read
Read Chapter
Read Chapter