This strictly arboreal lizard is abundant in the mixed broad-leafed forest near Uruapan. The lizards are exceedingly wary and can be approached only with difficulty. In life males have pale blue bellies; the throat is pale pink. The pale gray dorsum marked with irregular darker gray blotches blends well with the color of the tree trunks on which the lizard lives. The one specimen from Dos Aguas was found on a pine tree; it provides the only record for the species from the Sierra de Coalcoman.

~Sceloporus bulleri~ Boulenger

_Sceloporus bulleri_ Boulenger, Proc. Zool. Soc. London, 1894:729, April, 1895.--Las c.u.mbre de los Arrastrados, Jalisco, Mexico.

Acuaro de las Lleguas (13); Barolosa (9); Dos Aguas (61); 10 km. NE of Dos Aguas (5).

Heretofore this species has been known only from a few specimens from scattered localities in the Sierra Madre Occidental in southwestern Jalisco and Sinaloa. The collection of a large series of these lizards in virgin pine forest at elevations of more than 2000 meters in the Sierra de Coalcoman now makes possible an a.n.a.lysis of variation in the species.

Superficially _S. bulleri_ resembles _S. torquatus_, but _S. bulleri_ is smaller, has more dorsal scales, fewer scales in the dark collar, and fewer femoral pores. In 88 specimens of _S. bulleri_ there are 36-41 (38.7) dorsal scales and 2 or 3 (2.6) middorsal scales in the collar, as compared with 28-31 (29.3) dorsal scales and 3 or 4 (3.4) middorsal scales in the collar of 26 specimens of _S. torquatus_ from Uruapan. In 20 adult males of _S. bulleri_ there are 13-15 (14.3) femoral pores, and 13-16 (14.4) in 11 females; 13 males of _S. torquatus_ have 14-21 (17.3) femoral pores, and 13 females have 15-21 (16.7). Seventeen adult males of _S. bulleri_ have snout-vent lengths of 72-91 (82.0); ten females, 71-87 (75.7). In comparison, 13 adult males of _S. torquatus_ have an average snout-vent length of 88.9 mm., and 13 females, 88.5 mm. In _S.

bulleri_ there is little variation in the head scales. The frontal is in contact with the interparietal in 63, and not in 24, specimens; the median frontonasal is in contact with the frontal in 13, and not in 74, specimens. In 39 specimens there are two canthals, and in 48 there is one; in 29 specimens there are three preauriculars, and in 58 there are four.

In life adult males have a pale blue tail, bright blue belly patches, a purplish blue throat, and pale blue lines on the sides of the head and neck.

This species was obtained at four localities in the high mountains of the Sierra de Coalcoman. In this mountain range _Sceloporus bulleri_ apparently replaces _S. torquatus_, a species that is widespread in the Cordillera Volcanica and on the Mexican Plateau. At Dos Aguas and at Acuaro de las Lleguas the lizards were abundant in the tall pine forest, where they were found on standing pine trees, on pine logs, and on rock outcroppings.

~Sceloporus dugesi intermedius~ Duges

_Sceloporus intermedius_ Duges, La Naturaleza, 4:29, 1877.--La Noria, near Zamora, Michoacan, Mexico.

_Sceloporus dugesii intermedius_, Smith, Univ. Kansas Sci.

Bull., 24:663, February 16, 1938.

Cojumatlan (6); Jiquilpan (11); Lago de Camecuaro; Lago de Chapala; Morelia (23); Patzcuaro (84); Quiroga (35); Sahuayo (4); Tacicuaro (2); Tangamandapio (17); Tangancicuaro (9); Zacapu (4); Zamora (11); Zinapecuaro (9).

This lizard is strictly an inhabitant of the Mexican Plateau, where it is found in rocky places, sometimes in pine-oak forest, but more frequently in mesquite-gra.s.sland. It is a terrestrial species, and is most often seen on rock fences at elevations of 1500 to 2200 meters.

This species differs from _S. bulleri_ and _S. torquatus_ in having two rows of supraoculars, instead of one; also it has more dorsal scales.

Twenty-six specimens of _Sceloporus dugesi intermedius_ from Tangamandapio and Tangancicuaro have 44-48 (45.7) dorsal scales, as compared with an average of 38.7 in _S. bulleri_ and 29.3 in _S.

torquatus_. In life _Sceloporus dugesi intermedius_ has a dull greenish gray dorsum; in males the belly patches are bright blue bordered medially by black, and the throat is bluish gray. The largest specimen examined is a male having a snout-vent length of 80 mm.

~Sceloporus gadowae~ Boulenger

_Sceloporus gadoviae_ Boulenger, Proc. Zool. Soc. London, 1905, 2:246, October 7, 1905.--Mezquit.i.tlan, Guerrero, Mexico.

Chupio; El Sabino (77); La Playa (6); Rio Marquez, 10 km. S of Lombardia (11).

Although this species has a rather extensive range in the Balsas-Tepalcatepec Basin in the state of Michoacan, Guerrero, Morelos, and Puebla, it is only locally abundant in that area. Usually these lizards are found on rocky cliffs in which there are many crevices for cover. _Sceloporus gadowae_ is abundant on a conglomerate cliff along the Rio Marquez south of Lombardia. Although the closely related _S.

pyrocephalus_ is abundant in the stream valley and in the hills above the cliff, _S. gadowae_ has been found only on the cliff; few individuals of _S. pyrocephalus_ have been observed on the cliff. A similar situation was discovered on a much more extensive conglomerate cliff along the Rio Balsas near Mexcala, Guerrero. Near Tehuitzingo, Puebla, where _S. pyrocephalus_ was not found, _S. gadowae_ was found on conglomerate cliffs. Probably there is strong compet.i.tion between the two species; possibly this has resulted in the restriction of _S.

gadowae_ to isolated cliff-habitats within the extensive range of the more widespread _S. pyrocephalus_.

In Michoacan _Sceloporus gadowae_ has been found along the lower slopes of the Cordillera Volcanica at elevations from 250 to 1050 meters. All of the localities from which this lizard is known lie in the arid tropical scrub forest.

~Sceloporus grammicus microlepidotus~ Wiegmann

_Sceloporus microlepidotus_ Wiegmann, Herpetologia Mexicana, p. 51, 1834.--Mexico. Type locality restricted to Mexico, Distrito Federal, by Smith and Taylor (1950b:120).

_Sceloporus grammicus microlepidotus_, Smith and Laufe, Trans. Kansas Acad. Sci., 48:332, December, 1945.

Angahuari; Apo (10); Atzimba (3); Carapan (5); Cerro San Andres (17); Cerro Tancitaro (18); Corupu; Cuseno Station (2); Jacona; Jerahuaro (10); Macho de Agua; Mil c.u.mbres; 46 km. E of Morelia; 60 km. E of Morelia (2); Opopeo (14); Patzcuaro (30); Puerto Hondo (19); San Gregorio (41); San Jose de la c.u.mbre (8); Sierra Patamba; Tancitaro (233); Tupataro; Undameo; Uruapan (180); between Zacapu and Zamora; 24 km. SE of Zitacuaro; between Zurumbeneo and Cerro Garnica.

This small species of _Sceloporus_ is an ubiquitous inhabitant of the coniferous forests from 1550 to 3100 meters in the Cordillera Volcanica.

Usually it is seen on tree trunks, but occasionally on the ground. Near the lower limit of the alt.i.tudinal distribution of the species, as at Uruapan, individuals sometimes are found on broad-leafed trees.

Apparently _Sceloporus heterolepis_ replaces _S. grammicus microlepidotus_ in the Sierra de Coalcoman.

~Sceloporus heterolepis~ Boulenger

_Sceloporus heterolepis_ Boulenger, Proc. Zool. Soc. London, 1894:731, April, 1895.--La c.u.mbre de los Arrastrados, Jalisco, Mexico.

Araparicuaro; Cerro Barolosa (6); Dos Aguas (13); Los Conejos; 11 km. N of Uruapan (3).

Although Michoacan has not previously been included in the range of this lizard, it was first collected in the state by Gadow in 1908 (BMNH 1914.1.28.69 from Araparicuaro). The description of _S. heterolepis_ given by Smith (1939:197) can be supplemented by data on the 23 specimens now in the collections of the Museum of Zoology at the University of Michigan. All have two canthals; there are 55 to 71 (63.6) scales in the middorsal row; 1 to 3 rows middorsally are somewhat enlarged and bordered on either side by a row of larger scales bearing high keels. There are 14 to 20 (16.2) femoral pores. Eight adult males have snout-vent lengths from 49 to 61 (58.0) mm. and tail lengths from 57 to 74 (66.0) mm.; four adult females have snout-vent lengths from 52 to 57 (55.2) mm. and tail lengths from 60 to 66 (63.5) mm. The smallest of eight juveniles has a snout-vent length of 28 mm. and a tail length of 32 mm. The dorsum in adults is pale grayish brown; there are three irregular chevron-shaped dark marks and a triangular dark brown mark above the insertion of the hind limbs; on the tail are dark brown rings.

There are scattered faint blue flecks on the flanks and narrow transverse dark lines on the lower limbs. Males have pale bluish green belly patches and an orange-salmon-colored throat; the belly in females is pale orange-tan. The juveniles have a more contrasting color pattern; the dark chevrons on the dorsum are bordered posteriorly by pale gray.

In Michoacan this species has been obtained in pine and pine-fir forests from 1800 to 2700 meters. On Cerro Barolosa and at Dos Aguas, both in the Sierra de Coalcoman, the lizards were found beneath the bark of dead, standing pines. In the Sierra de Coalcoman _Sceloporus heterolepis_ seems to fill the niche of the small arboreal _Sceloporus_ in the coniferous forest in southwestern Mexico, a position held by _S.

grammicus microlepidotus_ in the Cordillera Volcanica; the latter species does not occur in the Sierra de Coalcoman. Five specimens of _Sceloporus heterolepis_ are known from the Cordillera Volcanica, whereas 603 of _S. grammicus microlepidotus_ have been collected there.

The ecological relationships that exist between the two species in the Cordillera Volcanica are not known.

Insofar as is known, _Sceloporus heterolepis_ reaches the southern limits of its range in the Sierra de Coalcoman and in the western part of the Cordillera Volcanica. Other records for the species are from the Sierra Madre Occidental in Jalisco. Langebartel (1959) described _Sceloporus shannonorum_ from the mountains near the Durango-Sinaloa border; the single specimen of _S. shannonorum_ differs significantly from _S. heterolepis_ only in having fewer dorsal scales (48). The acquisition of additional material, especially from Nayarit and northern Jalisco, probably will provide a basis for showing that these two populations are conspecific.

~Sceloporus horridus oligoporus~ Cope

_Sceloporus oligoporus_ Cope, Proc. Acad. Nat. Sci.

Philadelphia, 16:177, September 30, 1864.--Colima, Colima, Mexico.

_Sceloporus horridus oligoporus_, Taylor, Univ. Kansas Sci.

Bull., 24:520, February 16, 1938.

Aguililla; Apatzingan (50); Arteaga (2); Capirio (2); Cascada Tzararacua; Charapendo (4); Coahuayana (3); Coalcoman (32); 19 km. S of Corralito; 27 km. E of Dos Aguas; El Sabino (55); El Ticuiz; Huetamo (2); Jazmin; Jungapeo (2); La Orilla (2); La Placita; Limoncito (3); Playa Azul (5); Tzitzio (8); Uruapan (4); Volcan Jorullo (2); Ziracuaretiro; Zirimicuaro (13).

All of the specimens from Michoacan seem to be typical _S. horridus oligoporus_; none has more than six femoral pores.

Characteristically this species is found in open arid scrub forest; it reaches its greatest abundance in rocky areas in which there are scattered leguminous trees and bushes. It has been found in these low trees and bushes almost as frequently as it has been found on the ground; none has been seen in large trees or far above the ground.

Alt.i.tudinally, this species ranges from sea level to about 1600 meters.

~Sceloporus melanorhinus calligaster~ Smith

_Sceloporus melanorhinus calligaster_ Smith, Proc. U. S.

Natl. Mus., 92:360, November 5, 1942.--Acapulco, Guerrero, Mexico.

Aguililla; Apatzingan (18); Barranca de Herradero; Capirio (19); Coahuayana (4); Coalcoman (2); Cofradia (4); El Cerrito; El Sabino (33); El Ticuiz (3); La Placita (6); Lombardia (4); Playa Azul; Rio Marquez, 10 km. S of Lombardia (2); Rio Marquez, 13 km. SE of Nueva Italia (4); Salitre de Estopila; San Juan de Lima (2); Santa Ana; Tzitzio; Ziracuaretiro.