«Herpetologists' League Interesting Herpetological Records from Southern Texas and Northern Mexico Author(s): Ralph W. Axtell and Aaron O. Wasserman ...»
Interesting Herpetological Records from Southern Texas and Northern Mexico
Author(s): Ralph W. Axtell and Aaron O. Wasserman
Source: Herpetologica, Vol. 9, No. 1 (Jun. 1, 1953), pp. 1-6
Published by: Herpetologists' League
Stable URL: http://www.jstor.org/stable/3889877.
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http://www.jstor.org This content downloaded from 188.8.131.52 on Wed, 6 Aug 2014 17:52:11 PM All use subject to JSTOR Terms and Conditions HERPETOL Established 1936. Organ of the HERPETOLOGISTSLEAGUE, A.A.A.S. Associate. Society of SystematicZoology, Affiliate.
President, Dr. Hobart M. Smith. Vice-President, Dr. Angus M. Woodbury.
and Secretary-Treasurer Publisher,ChapmanGrant, Route 1, Box 80, Escondido, California Edited by the Officers. Policies determined by the Members. $3.00 per volume Vol. 9 June 1, 1953 Part 1 Interesting Herpetological Records from Southern Texas and Northern Mexico By RALPH W. AXTELL* and AARON 0. WASSERMAN** In an attemptto obtain live specimensof reptiles and amphibiansfor a regional display of the 1952 A.S.I.H. meeting in Austin, a collecting trip encompassing the Rio Grande Valley area of Texas and northern Tamaulipas,Mexico, was made by Henry Hildebrand*and the authors."* A total of 78 specimens was collected, most of which are in the Texas Natural History Collection (TNHC). The remainderare in the private collection of the senior author (RWA).
Total time in the field and traveling amountedto seven days, from December 26, 1951 to January1, 1952. A mild "norther"slowed collecting for the first few days, but we enjoyed optimum collecting conditions for the remainderof the trip.
We wish to extend our warmest thanks to the Ted Beimlers of Brownsville, who viewed our efforts with unfailing curiosity and sympathy, and who, through their hospitality,made our stay there very enjoyable.
The giant Mexican toad (Bufo hotribilis) has been previously recorded only once in Texas by Taylor and Wright (1932) near Zapata, Zapata County.
A single specimen of this species (TNHC 15000) was collected on December 30, 1951, at a location 8.5 miles west of Rio Grande City, and one-half mile north of Garceno,StarrCounty,Texas. It was taken at the edge of a dirt 'tank" around which Rana pipiens and Acris crepitans were numerous. The toad seems to be an immaturemale measuring122.0 mm. from snout to vent. Blair (1947) released several specimens of horribilis in the vicinity of Hebbronville, Jim Hogg County, but it is unlikely that the individual discussedhere is one of these.
The distributionof spadefoot toads in Texas is less well known than that of other anurans. A collection of Scaphio pus representing three species was made on December 31, 1951, about 10 miles south of Hebbronville, Jim Hogg County. This includesScaphiopusbombifronswhich has not been previouslyrecordedfrom southernTexas. All of these aniInstitute of Marine Science, University of Texas, Port Aransas.
**Dept. Zoology, University of Texas, Austin.
mals were collected shortly after midnight on an unnumberedmacadam road leading to Rio Grande City. No recorded rain fell in the general region (including the Garcenoarea) for at least three weeks prior to the time these animals were taken. And yet, the spadefoots were numerous on the highway (one or two every few yards). However, the humidity was quite high since the air felt damp and some mist was evident. The wind was from the southeast,and the temperature was in the high fifties or low sixties. The soil was a rich reddishcolor and of a fine sandy consistency.
Of the 40 spadefoots collected, 35 proved to be S. bombifrons. The largest of these measured54.6 mm. from snout to vent and the smallest
35.5 mm. Brown (1949) gave the range as northwesternand the TransPecos region of Texas. Firschein (1950) reportedthat several specimens of this species were collected near Samalayuca,Chihuahua,Mexico, in 1947 and again in 1949. W. F. Blair and party collected a number of S. bombifrons 10 miles northeastof Lamesa,Dawson County, Texas, in July, 1952.
The 25 bombifronswhich were preservedwere comparedwith other examples of the plains spadefoot from Dawson, Hutchinson and Armstrong counties of west Texas. The differences between these samples and our specimens were negligible.
The occurrenceof this species in southernTexas is not surprisingas numerous other vertebrateswhich are widely distributed in the plains region of west Texas range eastwardinto the brushlandsof south Texas, avoiding the Edwards Plateau. In view of the present evidence, this would seem to be true in the case of S. bombifrons.
Of the remainingfive animals, four are S. hurteri and one S. couchi.
The largest of the former measures60 mm., the smallest 32 mm. from snout to vent; and the latter is 63.8 mm.
It should be noted that all of the Scaphiopuswere collected within a 10 mile stretch of road, indicating the occurrenceof the three different species of spadefoots in the same region.
Five specimensof Holbrookiapropinquapropinqua (TNHC 15001-2 and RWA 535-5) were collected 20 miles E.S.E. of Matamoros,Tamaulipas, Mexico. The individuals,which are all juveniles, were found active on sparselyvegetated sand dunes within 300 feet of the Gulf of Mexico.
This record definitely establishes the subspeciespropinquaas a resident of Mexico and extends its range 20 miles south of its previous known range in Texas.
Our use of the trinomial is in following with the recent paper of P.
W. Smith and W. L. Burger (1950) describingH. p. piperata, a new subspecies of the keeled earless lizard from northern Veracruz,Mexico.
Our concurrence with the nomenclatorial views of Smith and Burgerdoes not mean complete agreement with them, however, for a number of ambiguitieswere found in their paper which we feel should be pointed out.
Smith and Burger write: "The specimens (piperata) are uniformly white below, in contrastto the tawny or yellow venters of most preserved Holbrookia propinqua propinqua." This contrastis apparentlyset up as PLATE 1. Lampropeltistriangulum annulata x gentilis, 992 mm. total length. Collected 1 mile southeastof Hebbronville,Jim Hogg Co., Texas.
Photo by Isabelle Hunt Conant.
one of the differencesbetween the two subspecies,but qualifiedby insertbefore the lizard'sname. If taxonomicdifferencesinvolving "preserved" ing coloration are to be employed, it would seem to the present authors that the proposed entities used should be in the same state of preservation. Certainlymany color differencesin reptiles could be found if old preservedmaterialwere comparedwith living or freshly preservedspecimens. That H. p. propinqua possesses a white ventral surface is a fact well known to anyone who has observedit in life.
The senior author, who has worked extensively with Holbrookia in the field and lab, has noted the pinkish colorationof the females not only in H. propinqua,as Smith and Burger suggest, but in the gravid females of Holbrookia maculata, Holbrookia texana, and as recently pointed out by Shaw (1953) in Crotaphytus collaris, and also by Fitch and Tanner (1951) in Crotaphytus, and Gambelia wislizeni. Of these mentioned, only maculataand propinqua exhibit this striking color on the ventral surface of the tail.
In order to see how other charactersof piperataheld up, 158 H. p.
propinquawere examinedfrom all partsof its known range. Eleven were found to have the transverserow of four subequalscales the key character for piperata. These eleven specimens came from widely separated localities and showed no general clinal trend either to the north or south.
One of the Tamaulipasspecimensherein reported (RWA 533) revealed while the remaining specimens showing it were the scale characteristic, from Aransas,Atacosa,Bexar, and Nueces Countiesof Texas. Although a large series (40) were examinedfrom Kenedy County,none displayedthe requiredscalation,but a numberclosely approached it.
Summarizingthis information with some additional observationsnot
discussed at length above, we have:
Differentiating charactersset forth by Smith and Burger separating H. p. piperata from H. p. propinqua and our findings with propinqua piperata propinqua
1. white venter white venter
2. pinkish colorationon tails of females same transverserow of gulars in 4 specimens in 11 out of 158 specimens 3.
4. enlarged supraoculars enlarged supraoculars
5. elevated, triangularcircumorbitals elevated quadrangular circumorbitals
6. ground color dorsallydarkgray finely speckled with white variable
7. two rows of small dark blotches same
8. tail bicolored same It would seem that morphological differences between piperata and typical propinqua is not complete, as Smith and Burger have asserted.
Retention of the subspecificname piperata in the present paper is based on the meager but significant evidence presented above. To strengthen the evidence in favor of the race described by Smith and Burger, it may be pertinenthere to mention the importanttransitionzone between Nearctic and Neotropical faunal elements in southern Tamaulipas.
Without going into much detail here, it should be pointed out that a large proportion of the lowland Neotropical fauna and flora of Mexico find their northern limits within this transitionzone, and vice versa. In This content downloaded from 184.108.40.206 on Wed, 6 Aug 2014 17:52:11 PM All use subject to JSTOR Terms and Conditions 1953 HERPETOLOGICA 5 addition, many forms that have not been limited have differentiatedinto separateraces on opposing sides of this same region. Reptilian examples such as Bothrops atrox, Boa constrictor,Laemanctus serratus,Crocodylus moreleti are limited Neotropical forms; Masticophisflagellum, Gopherus berlandieri, Holbrookia texana are limited Nearctic forms; and Lampropeltis trianguluem,Sceloporus variabilis, Cnemidophorus sacki are forms that have differentiatedinto subspecies on opposite sides of the zone.
The propinqua-piperata split, if there is one, could easily fit in with the last group mentioned above. The answerto this questionwill be conclusive only after more than four specimensof piperatabecome available for study, and after the range and variabilityof propinquain Tamaulipas become better known.
Three specimens of Eumeces tetragrammus (Baird) (TNHC 14998RWA 570) were taken one mile east of Los Fresnos, Cameron County, Texas. All individualsagree well with published descriptionsof this form. The skinks were found in cavities between truncated frond husks of the common introduced palm (Phoenix canariensis) found in the valley area. This winter habitatof tetragrammus had been discovered some years before by Mrs. Ted Beimler, who very courteouslydemonstrated her collecting technique; it was through the use of this technique that we acquired our specimens. The lizards seem to prefer half-grown palms, which retain moisture near the proximal portion of their husks.
Collecting is effectedby disengagingthe husks from the tree with a potato fork or similar instrument. The skink, upon being exposed, quickly darts for cover, and one must be alert to capturethe creature. This method of collecting is erratic, however, as 25 or 30 trees may be tested without finding a single specimen. At other times, a single tree may contain five or six lizards.
A single specimen of Lampropeltistriangulumwas taken A.O.R. one mile southeast of Hebbronville, Jim Hogg County, Texas, December 21,
1951. The snake is still living, and has increased in size, although no exact growth measurementshave been taken. Total length at time of writing (Jan. 10, 1953) is 992 mm.; tail length, 130 mm.; girth at midbody, 69 mm.; head length, 24.6 mm.; head width, 14.9 mm.; scale rows, 21-21-19; ventrals, 201; subcaudals,57; supralabials,7-7; infralabials, 8-9; preoculars,1-1; postoculars,2-2; temporals,2-3; 22 yellowish-white annuli on body, 6 on tail.
The pattern of the present specimen differs from H. M. Smith's (1942) diagnosis of annulata in a number of ways: (1) The snout has whitish markson the rostral,internasals,in the preocularregion, and on the first 4 supralabials. (2) The red bands are not excessively broad (first red band longest-6 scale lengths, average 21/2 scale lengths), and three sets of black rings are confluent acrossthe red areas dorsally. (3) The black areas of the ventrum are only slightly broaderthan the intervening white areas.
Blanchard (1921), on the other hand, mentions the above numbered pattern characteristics his diagnosis of annulata, but states that these in characteristicsare found in specimens from a more northerly portion (Brownsville region) of the range. ApparentlyBlanchardis here hinting at intergradationbetween annulata and gentilis, for a few paragraphs later he states that annulata differs from gentilis "(1) in having the
snout nearly or entirely black instead of lightened on the end; (2) in having the white rings of about the same width on sides and belly as on the middorsal line, instead of widened there; (3) in having the belly marked with broad areas of black and white; and (4) in having a distinctly higher averagenumberof ventralplates." It should be noted then, that our specimen, which disagrees to a limited extent with all of Blanchard's points, would actually be more like gentilis than annulata.
This fact becomes even more apparent when our specimen very easily keys to gentilis (has 28 white annuli, see Plate I) in Perkins (1949) and Schmidt and Davis (1941).