Читать книгу The Amphibians and Reptiles of Michoacán, México - William Edward Duellman - Страница 13

Ambystoma amblycephalum Taylor

Ambystoma amblycephala Taylor, Univ. Kansas Sci. Bull., 26: 420, November 27, 1940.—Fifteen kilometers west of Morelia, Michoacán, México.

Fifteen km. W of Morelia (19); 11 km. SSE of Opopeo (12); 8 km. S of Pátzcuaro; 24 km. S of Pátzcuaro (2); Quiroga (20); Tacícuaro (167).

Taylor and Smith (1945:530) presented data on 137 specimens collected at Tacícuaro on October 1, 1939; these are all larvae and metamorphosing individuals. Aside from these, the largest larva examined (UMMZ 104962 from 15 km. W of Morelia) has a snout-vent length of 70.0 mm. and a tail length of 53.5 mm. The larvae are pale pinkish tan above and somewhat paler below; there is a lateral row of cream colored spots. The tail-fin, which is deepest at mid-length, extends to the back of the head and is flecked with brown. In small larvae the outer edge of the tail-fin is dark brown. The eyes are large. Two small metamorphosed specimens (UMMZ 98967) from 24 kilometers south of Pátzcuaro are tentatively referred to this species. These specimens have body lengths of 49.0 and 45.0 mm. and tail lengths of 36.0 and 31.5 mm., respectively. They have 17–17 and 16–15 vomerine teeth arranged in a broad arch behind the choanae, 10 costal grooves, and 7 intercostal spaces between adpressed toes. The dorsal color is uniform brown; that of the venter is a dusty cream.

Larvae were collected from shallow ponds near Quiroga and 15 kilometers west of Morelia; metamorphosed individuals were taken from beneath logs in pine and fir forests at elevations from 2300 to 2800 meters.

Ambystoma dumerili dumerili (Dugès)

Siredon Dumerili Dugès, La Naturaleza, 1:241, 1870—Lago de Pátzcuaro, Michoacán, México.

Bathysiredon dumerilii, Dunn, Notulae Naturae, 36:1, November 9, 1939.

Bathysiredon dumerilii dumerilii, Maldonado-Koerdell, Mem. y Rev. Acad. Nac. Cien., 56:199, 1948.

Ambystoma (Bathysiredon) dumerili, Tihen, Bull. Florida State Mus., 3:3, June 20, 1958.

Lago de Pátzcuaro (22);? Morelia.

For many years this unusual salamander was known from only a few specimens mostly collected in the last century; Smith and Taylor (1948:7) stated: "It is presumed that this species is extinct owing to the introduction of exotic game and food fishes." In 1951 and in 1955 I had been told that axolotls were sold in the market at Pátzcuaro; nevertheless, none was found on my visits there. In 1956 Charles M. Bogert obtained several large specimens at the market in Pátzcuaro. These establish the continued existence of the salamander in Lago de Pátzcuaro. On January 27, 1955, R. W. Dickerman procured a specimen (KU 41573) in the market at Morelia. Since fish are brought to Morelia from Lago de Pátzcuaro, the specimen probably was from that lake. Nevertheless, the species may occur in other permanent bodies of water in Michoacán. Maldonado-Koerdell (1948) described Bathysiredon dumerili queretarensis from San Juan del Río, Queretaro. This locality is about 200 airline kilometers northeast of Lago de Pátzcuaro and is in the Río Moctezuma drainage.

Ambystoma ordinarium Taylor

Ambystoma ordinaria Taylor, Univ. Kansas Sci. Bull., 26:422, November 27, 1940.—Four miles west of El Mirador, near Puerto Hondo, Michoacán, México.

Axolotl (56); Cerro San Andrés; 22 km. W of Mil Cumbres; 46 km. E of Morelia (34); 8 km. SE of Opopeo (5); Puerto de Garnica (8); Puerto Hondo (41); San Gregorio (16); San José de la Cumbre (20).

Of 16 specimens (KU 51520–35) collected on June 18, 1955, near San Gregorio, 15 are adult females with swollen cloacae and minute ovarian eggs. Possibly these specimens had just recently deposited their mature eggs. In preservative the specimens are black above and dull creamy gray below. Measurements for the 15 females are: snout-vent length, 80.0–102.0 (92.5); tail length, 69.0–93.0 (84.2); head width, 15.8–20.5 (17.7); head length, 22.8–26.6 (24.4). A larval specimen with small gills has a snout-vent length of 72 mm. and a tail length of 62 mm. Three specimens have 12 costal grooves; the other have 11.

Of 20 specimens from San José de la Cumbre (UMMZ 112857 and 115143), 14 are neotenic adults; the others are larvae. In life the salamanders were blackish to olive-brown above with scattered cream-colored dots on the dorsum and flanks but in preservative are dull grayish black with indistinct pale spots and dark reticulations. The belly is pale gray with indistinct dark spots. Eleven females and three males have the following measurements, respectively: snout-vent length, 76.0–90.0 (80.7), 64.0–84.0 (74.3); tail length, 70.0–81.0 (75.0), 58.0–71.0 (66.7); head width, 19.5–23.5 (20.7), 17.5–20.5 (19.3); head length, 22.0–25.0 (23.0), 20.0–22.5 (21.5). The smallest larva has a snout-vent length of 43.0 mm. and a tail length of 38.0 mm. Two individuals have 12 costal grooves; the others have 11. All of the females contained eggs, the largest of which were 1.5 mm. in diameter. The stomachs of most of the specimens were distended with oligochaets, aquatic insect larvae, and small aquatic beetles.

A series of 34 larvae (JRD 5904–37) from 46 kilometers east of Morelia are tentatively referred to this species. These specimens are olive-brown above with cream-colored spots on the flanks; the dorsal tail-fin does not extend onto the body.

This species has been found only at elevations in excess of 2400 meters in pine and fir forests. At Rancho Axolotl James A. Peters collected larvae and neotenic individuals in a rocky stream and adults from beneath rocks and logs in the forest near the stream. Neotenic individuals and larvae were found in a clear stream in pine-fir forest at an elevation of 2700 meters near San José de la Cumbre; specimens were collected there in July, 1955, and again in July, 1956. The site was visited in April, 1956, at which time the stream consisted of only a few puddles; no salamanders were found.

Ambystoma tigrinum velasci Dugès

Ambystoma velasci Dugès, La Naturaleza, ser. 2, 1:142, 1888.—Laguna Santa Isabel, near Guadalupe Hidalgo, Distrito Federal, México.

Ambystoma tigrinum velasci, Dunn, Copeia, no. 3:157, November 14, 1940.

Pátzcuaro (5); Tacícuaro (9).

Definite specific assignment of these specimens, all larvae, cannot be made at this time. They have shovel-shaped heads and laterally compressed bodies with the dorsal tail-fin extending anteriorly to the back of the head. The eyes are small. The body is pale tan with dark mottling on the tail and flanks. The average snout-vent length for nine specimens from Tacícuaro is 61.0 mm.

The larvae from Tacícuaro (UMMZ 89255) were collected by Dyfrig Forbes in October, 1939; those from Pátzcuaro, presumably Lago de Pátzcuaro (BMNH 1914.1.28–247-8 and CNHM 948), were collected by Hans Gadow and Seth Meek in 1908.

Pseudoeurycea belli (Gray)

Spelerpes belli Gray, Catalogue Batrachia Gradientia British Museum, p. 46, 1850.—México. Type locality restricted to 2 miles east of Río Frío, Puebla, México, by Smith and Taylor (1950a:341).

Pseudoeurycea bellii, Taylor, Univ. Kansas Sci. Bull., 30:209, June 12, 1944.

Axolotl (2); Carapan; Cerro Tancítaro (84); Macho de Agua; 22 km. W of Mil Cumbres; Opopeo; Pátzcuaro (8); Puerto Hondo (2): San José de la Cumbre; San Juan de Parangaricutiro (42); Uruapan (5); Zacapu (4).

This salamander seems to reach its greatest abundance in Michoacán in the Sierra de los Tarascos between Pátzcuaro and Tancítaro, where it is found at elevations from 1500 to 2900 meters. It is found less commonly in the eastern part of the Cordillera Volcánica in Michoacán, where it sometimes occurs in association with Pseudoeurycea robertsi.

On June 22 and 23, 1955, four clutches of eggs of this species were found beneath adobe bricks and rocks on the volcanic ash that has buried the village of San Juan de Parangaricutiro. The eggs were unstalked and separate, but adherent in clumps of three or four (Pl. 2, Fig. 1). The outer membranes were covered with fine particles of ash. The ash beneath the stones where the eggs were found was only slightly moist; one clump of eggs was partially desiccated. Three complete clutches have 20, 23, and 34 eggs; one clutch of 15 eggs was being eaten by beetles (Tenebrionidae: Eleodes sp.). The eggs vary in size from 4.6 to 6.5 mm. and average 5.3 mm. in diameter. They are unpigmented. Surrounding the embryo is a vitelline membrane, an inner, and an outer envelope (Fig. 1). In an average-sized egg having an embryo 4 mm. in length, the diameter of the outer membrane is 5.3 mm., the inner membrane 5.0 mm., and the vitelline membrane 4.6 mm. All of the eggs contained embryos in which the limb buds were developed; in about half of these the eyes were distinctly visible.

Fig. 1. Diagram of an egg of Pseudoeurycea belli from San Juan de Parangaricutiro, Michoacán. × 10.

The first heavy rain of the season occurred on the night of June 22, 1955. Thus, at least sometimes, Pseudoeurycea belli lays its eggs before the onset of the rainy season. A female having a snout-vent length of 110 mm., collected on June 22, 1955, contained 36 ovarian eggs having diameters from 3.0 to 3.5 mm. The fact that small juveniles were collected on the same date indicates that this salamander lays eggs over a period of several weeks in late spring and early summer.

The smallest juvenile examined has a snout-vent length of 17.0 mm. and a tail length of 7.5 mm. Twelve juveniles from the vicinity of San Juan de Parangaricutiro have an average snout-vent length of 19.4 mm. and an average tail length of 9.7 mm. In juveniles the adpressed limbs either touch or overlap by one intercostal space; in adults there are two or three intercostal spaces between adpressed toes. Therefore the greatest number of intercostal spaces between adpressed limbs is found in the largest specimens. A similar relationship between adpressed limbs (= length of limbs) and snout-vent length was shown for Plethodon richmondi by Duellman (1954a). The number of vomerine teeth is variable; the number of teeth seems to be closely correlated with the size of the salamander (Fig. 2). A similar correlation between the number of maxillary teeth and body length was reported for Chiropterotriton multidentatus by Rabb (1958). In 12 juvenile Pseudoeurycea belli there are 6–13 (8.8) vomerine teeth, and in 11 adults having snout-vent lengths greater than 90 mm. there are 39–49 (44.0) vomerine teeth. The coloration of the juveniles resembles that of the adults (Pl. 1).