Part 3

A: pipilans nebulosus B: pipilans pipilans C: modestus D: pallidus E: teretistes F: nivocolimae G: interorbitalis

========================================================================== Snout-vent Tibia Head Tympanum/ Eyelid/ length length/ width/ Eye Interorbital Species Sex N (SVL) SVL SVL -------------------------------------------------------------------------- A 17 22.9-28.5 38.1-42.0 34.4-37.2 36.6-47.8 56.1-82.4 (40.0) (35.4) (43.6) (68.2) 3 21.1-22.7 42.1-44.5 33.2-35.8 36.6-47.6 64.3-65.4

B 18 22.6-27.8 37.9-44.0 32.2-36.5 38.0-54.0 56.1-79.5 (41.4) (33.0) (46.2) (67.3) 1 29.4 38.4 32.5 44.6 55.0

C 8 15.8-20.1 38.5-42.6 32.1-38.1 26.8-39.3 57.0-86.9 (40.6) (34.2) (31.5) (69.1) 1 18.5 44.2 36.0 24.0 52.1

D 6 17.9-19.3 41.0-44.9 32.6-36.2 27.0-35.6 59.4-67.7 (43.4) (35.2) (30.9) (65.2)

E 18 19.2-23.2 41.5-45.3 32.5-36.4 28.6-43.8 51.2-75.0 (43.7) (34.0) (33.7) (62.2) 1 24.8 41.8 30.8 37.9 60.5

F 15 18.9-21.1 42.2-48.6 30.9-37.1 30.0-39.3 42.6-69.1 (45.0) (33.7) (34.7) (55.0) 1 24.1 40.9 33.5 27.6 56.5

G 1 25.6 43.0 ---- 39.4 57.6 9 20.2-26.7 39.9-47.1 32.6-39.3 29.1-41.2 58.2-76.9 (43.2) (35.8) (36.4) (69.2) ==========================================================================

In S. cystignathoides and leprus, the first finger is longer than the second, and the first two fingers are equal in length in guttilatus and marnockii. In the other species the first finger is shorter than the second.

Supernumerary tubercles are well developed on the plantar surfaces in all species, except S. guttilatus, in which they are poorly defined (Fig. 3). The relative sizes of the metatarsal tubercles has been used in the classification of the species and species groups of Syrrhophus. The metatarsal tubercles are similar in all species of the eastern complex (including rubrimaculatus); the outer tubercle is always about one-half the size of the ovoid inner metatarsal tubercle. In the leprus group the outer tubercle is conical and compressed. The metatarsal tubercles of pipilans are about the same size, or the outer is slightly smaller than the inner. In the modestus group the outer metatarsal tubercle is about one-third the size of the inner.

All species, except guttilatus, have well-defined to poorly defined lateral fringes on the toes. All species have expanded toe pads. The fifth toe is usually shorter than the third, but the second is equal in length to the fifth in some specimens of S. cystignathoides and S. marnockii. Syrrhophus nivocolimae is the only species with tubercles along the outer edge of the tarsus; this is merely a reflection of the highly tuberculate nature of the skin in this species.

Skin texture.--The skin of the dorsum is smooth or very weakly pustular in all species of the genus except nivocolimae and verrucipes. The dorsal surfaces of nivocolimae are warty; in verrucipes the skin is pustular. The skin of the venter is areolate in cystignathoides cystignathoides, dennisi and verrucipes but is smooth in all other species of the genus.

Color pattern.--As is evident in the diagnoses, the color patterns of given populations have been regarded as useful in separating the species and subspecies. Duellman (1958) suggested that the coloration, with the exception of modestus, was a dark ground color with pale markings. It is a moot point whether the frogs have light spots on a dark background or have a light background with an extensive reticulate dark pattern. The venters are gray or white, and the vocal sac is nearly black in some species. Interorbital dark bars or triangles are absent in only two species of the eastern complex, cystignathoides campi and marnockii; the latter lacks a supratympanic stripe, which is present in the other members of the eastern complex. Syrrhophus interorbitalis and nivocolimae have light interorbital bars; these bars occur in only one other population of the genus (S. c. cystignathoides). Bars on the thighs are ill defined or absent in the members of the marnockii and part of the modestus groups. The color in life is noted in the species accounts.

Voice.--The voices of all Syrrhophus can be described as a single short chirp or peep; without audiospectrographic analyses the significance of the differences between a chirp, peep, or short whistle cannot be appreciated. Martin (1958) and Wright and Wright (1949) reported multi-noted calls, and one collector of S. verrucipes noted the frog "trilled."

Fouquette (1960) presented analyses of two species (marnockii and pipilans nebulosus). The voices were very similar; both frogs were reported to "trill" and "chirp."

SYSTEMATIC ACCOUNT

The genus Syrrhophus has been defined (Lynch, 1968) and limited to the group of species occurring in Guatemala, Mexico and the United States. The closest relatives of Syrrhophus are the frogs of the genus Tomodactylus (Dixon, 1957; Firschein, 1954). Lynch (1968) implied there were no osteological bases for the separation of Eleutherodactylus, Syrrhophus, and Tomodactylus. At that time, I believed such to be the case and derived Syrrhophus and Tomodactylus from the rhodopis complex of Eleutherodactylus, with which they share terrestrial habits and relatively short limbs. In the rhodopis complex there is a tendency for the loss of the outer palmar tubercle, a not uncommon condition in Syrrhophus and Tomodactylus.

However, the skulls of Syrrhophus and Tomodactylus show departures from the pattern observed in the Middle American Eleutherodactylus, as well as many of those species in western South America. Baldauf and Tanzer (1965) reported that the frontoparietals and prootics were fused in Syrrhophus marnockii and that the prootics and exoccipitals appeared to be one bone (otoccipital). The otoccipital is not uncommon in eleutherodactyline frogs, but the fusion of the frontoparietals with the prootics (regardless of the fusion of the latter with the exoccipital) is uncommon in the family. I have found the frontoparietal-prootic fusion only in Syrrhophus (all species), Tomodactylus (all species), and Eleutherodactylus (West Indies species). None of the Middle American Eleutherodactylus has the two bones fused. Examination of the character is difficult in dried skeletal preparations. Cleared and stained or macerated preparations are satisfactory for checking this character.

Thus, in addition to the presence of numerous plantar supernumerary tubercles in the frogs of the genera Syrrhophus and Tomodactylus, these two genera can be separated from other Middle American eleutherodactylines by the fusion of the frontoparietals and prootics. This character not only further strengthens the argument that the two genera are closely related but poses a problem of zoogeographic analysis of the distribution of the character, which will be discussed fully elsewhere.

Key to the Species of the Frog Genus Syrrhophus

1. Three large, well-developed palmar tubercles 2

Two large palmar tubercles; outer (third) palmar tubercle reduced in size or absent 9

2. Digital pads more than twice (usually three or more) times width of digit 3

Digital pads less than twice width of digit 4

3. Males having vocal slits; dorsum vermiculate; diameter of tympanum in males about one-half diameter of eye S. dennisi

Males lacking vocal slits; dorsum flecked, spotted, or blotched; diameter of tympanum in male about three-fourths that of eye S. longipes

4. First finger longer than second 5

First finger shorter than or equal to second 7