Part 2

The definitions and contents of the five species groups are as follows:

leprus group: digital pads not or only slightly expanded, rounded in outline; first finger longer or shorter than second; snout acuminate or subacuminate, not rounded; outer metatarsal tubercle conical; digits lacking distinct lateral fringes.

content: cystignathoides, leprus and rubrimaculatus.

longipes group: digital pads widely expanded, triangular in outline; first finger shorter than second; snout acuminate; outer metatarsal tubercle not conical; digits bearing lateral fringes.

content: dennisi and longipes.

marnockii group: digital pads expanded, rounded to truncate in outline; first finger equal in length to second or slightly shorter; snout rounded; outer metatarsal tubercle not conical; digits lacking lateral fringes; generally stout-bodied frogs.

content: guttilatus, marnockii, and verrucipes.

modestus group: digital pads expanded, truncate in outline; first and second fingers subequal in length, first usually slightly shorter than second; snout subacuminate; inner metatarsal tubercle twice as large (or larger) as outer metatarsal tubercle; digits bearing poorly-defined lateral fringes.

content: interorbitalis, modestus, nivocolimae, pallidus, and teretistes.

pipilans group: digital pads not or only slightly expanded, truncate in outline; first finger equal in length to second; snout subacuminate; metatarsal tubercles subequal in size; digits lacking lateral fringes.

content: pipilans.

Acknowledgments.--For loan of specimens, I am indebted to Richard J. Baldauf, Texas A & M University (TCWC); W. Frank Blair, University of Texas (TNHC); Charles M. Bogert and Richard G. Zweifel, American Museum of Natural History (AMNH); James E. Boehlke and Edmond V. Malnate, Academy of Natural Sciences of Philadelphia (ANSP); Robert F. Inger and Hymen Marx, Field Museum of Natural History (FMNH); Ernest A. Liner (EAL); Michael Ovchynnyk, Michigan State University collection (MSU); James A. Peters, United States National Museum (USNM); Douglas A. Rossman, Louisiana State University Museum of Zoology (LSUMZ); Hobart M. Smith, University of Illinois Museum of Natural History (UIMNH); Charles F. Walker, University of Michigan Museum of Zoology (UMMZ); and John W. Wright, Los Angeles County Museum (LACM). Specimens in the collection at the University of Kansas Museum of Natural History are identified as KU. The abbreviations EHT-HMS refer to the Edward H. Taylor-Hobart M. Smith collection and FAS to the Frederick A. Shannon collection. The type-specimens from these collections are now in the Field Museum of Natural History and the University of Illinois Museum of Natural History.

I have profited from discussions concerning this problem with several persons, most notably William E. Duellman, Hobart M. Smith, Edward H. Taylor and Charles F. Walker. Nevertheless, the ideas and conclusions presented here should not be construed as necessarily reflecting their opinions.

David M. Dennis executed all of the figures, and my wife, Marsha, typed the manuscript.

Materials and Methods.--In the course of this study, 1003 specimens of the genus were examined. The holotypes of 21 of the 23 nominal species are extant; I have examined 19 of these. Nine measurements were taken, and five ratios computed for each of 338 specimens. Females are available for all species but one; thus, measurements were taken on individuals of both sexes.

ANALYSIS OF CHARACTERS

Size and proportions.--Frogs of this genus range in size from 16 to 40 mm. in snout-vent length. Five species are relatively small: S. cystignathoides, modestus, nivocolimae, pallidus and rubrimaculatus; one, S. longipes, is relatively large, and the remaining eight species are intermediate in size (22-30 mm.).

Males are generally smaller than females and have proportionately longer heads and usually larger tympani. No significant differences were found among proportions, except that S. longipes has a larger tympanum/eye ratio than any other species. Frogs in the Syrrhophus marnockii group tend to have shorter shanks and feet, thereby giving those species a more stocky appearance. However, the differences are not significant.

A summary of the data on size and proportions for the frogs of the genus Syrrhophus is given in Tables 4, 5, and 6.

Hands and Feet.--Taylor and Smith (1945), Smith and Taylor (1948), Firschein (1954) and Duellman (1958) discussed the value of the palmar tubercles in identifying frogs of this genus. The eastern complex in general has a well-developed outer palmar tubercle (Fig. 1) in distinction to the western complex in which the outer palmar tubercle is reduced or absent (Fig. 2). Dixon and Webb (1966) imply that the outer palmar tubercle is rarely absent but is usually smaller than the first supernumerary tubercle of the fourth finger. My study of the western species demonstrates that the outer palmar tubercle is indeed usually present and smaller than the first supernumerary tubercle.

Differences in interpretation of the terms "unexpanded" and "narrow," as well as differences in techniques of preservation, have led to confusion of the reported digital shapes in various species. Constant specific differences are evident in the hands (Fig. 1). Except in the cases of excessive uptake of fluids, all species have a terminal transverse groove at the tip of each digit. Taylor (1940b) stated that S. smithi lacked grooves, but examination of the holotype reveals faint grooves at the tops of the digits. Syrrhophus guttilatus, leprus, pipilans, and verrucipes lack lateral fringes on the fingers. Lateral fringes are well developed in the longipes and modestus groups but poorly defined or absent in the other members of the genus. The digital pads of the frogs of the longipes group are much broader than those of the other species and are narrowest in the frogs of the leprus group. Supernumerary tubercles are present on the palmar surfaces of all species of the genus.

TABLE 4--Size and Proportions in the Frogs of the Syrrhophus leprus Group.

A: cystignathoides campi B: c. cystignathoides C: leprus D: rubrimaculatus

========================================================================== Snout-vent Tibia Head Tympanum/ Eyelid/ length length/ width/ Eye Interorbital Species Sex N (SVL) SVL SVL -------------------------------------------------------------------------- A 33 16.3-23.5 41.3-49.6 34.0-40.1 43.7-66.5 43.2-89.6 (45.8) (37.0) (56.2) (61.5) 12 16.0-25.8 41.5-51.0 33.0-38.0 42.8-60.0 48.2-69.2 (45.8) (35.0) (51.2) (60.1) B 15 16.8-22.1 45.1-50.4 33.2-40.7 44.3-68.7 44.6-65.4 (47.3) (37.8) (54.8) (60.0) 6 19.6-24.2 46.4-50.0 34.1-38.1 43.3-56.5 53.2-65.4 (47.6) (36.2) (46.9) (59.2) C 14 20.6-26.4 42.3-52.3 35.0-40.3 47.5-62.5 58.2-72.5 (46.8) (37.4) (56.5) (67.3) 15 22.1-29.2 43.4-53.3 32.6-38.9 38.6-57.9 50.2-86.9 (47.1) (35.8) (47.1) (68.1) D 12 18.2-23.5 40.4-46.2 31.8-35.5 35.5-46.5 65.1-78.5 (43.4) (33.8) (41.7) (71.7) ==========================================================================

TABLE 5--Size and Proportions in the Frogs of the Syrrhophus longipes and S. marnockii Groups.

A: dennisi B: longipes C: guttilatus D: marnockii E: verrucipes

========================================================================== Snout-vent Tibia Head Tympanum/ Eyelid/ length length/ width/ Eye Interorbital Species Sex N (SVL) SVL SVL -------------------------------------------------------------------------- A 16 22.8-28.4 43.9-49.7 35.3-41.2 53.9-64.2 55.3-74.0 (47.4) (38.8) (58.9) (65.1) 10 25.9-32.0 46.3-50.8 35.6-40.3 50.6-58.7 58.1-70.9 (48.2) (37.7) (54.9) (63.6) B 22 22.1-33.2 45.8-51.7 38.7-44.4 61.1-87.2 61.5-83.0 (48.4) (41.8) (72.0) (72.0) 19 26.8-39.6 44.3-51.0 36.3-40.8 49.5-72.1 55.3-85.9 (47.2) (39.1) (59.5) (67.9) C 19 20.6-29.0 41.2-48.1 36.9-44.9 55.1-75.7 53.3-79.5 (44.5) (40.6) (64.1) (66.0) 5 25.7-31.0 41.4-46.8 35.9-42.3 47.6-61.7 62.3-79.8 (43.6) (38.5) (54.0) (72.9) D 14 18.4-28.9 42.3-47.2 36.1-43.0 47.2-68.3 51.6-74.4 (44.1) (39.6) (61.2) (66.3) 29 20.4-35.4 38.7-46.4 35.9-41.3 45.8-73.3 52.1-70.5 (42.7) (38.2) (60.3) (60.7) E 29 17.5-29.2 42.7-49.5 36.2-42.4 56.1-82.2 56.8-82.8 (46.3) (39.1) (67.8) (70.4) 6 26.5-31.7 42.4-47.7 36.0-38.1 45.8-57.8 61.0-77.9 (44.6) (37.0) (53.9) (69.0) ==========================================================================

TABLE 6--Size and Proportions in the Frogs of the Syrrhophus pipilans and S. modestus Groups.