AmphibiaWeb - Eleutherodactylus cystignathoides
Eleutherodactylus cystignathoides
Rio Grande Chirping Frog, Lowland Chirping Frog
Subgenus: Syrrhophus
family: Eleutherodactylidae
subfamily: Eleutherodactylinae

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Conservation Status (definitions)
IUCN (Red List) Status Least Concern (LC)
NatureServe Status Use NatureServe Explorer to see status.
National Status None
Regional Status None
Access Conservation Needs Assessment Report.



View distribution map in BerkeleyMapper.
View Bd and Bsal data (7 records).

bookcover The following account is modified from Amphibian Declines: The Conservation Status of United States Species, edited by Michael Lannoo (©2005 by the Regents of the University of California), used with permission of University of California Press. The book is available from UC Press.

Eleutherodactylus (= Syrrhophus) cystignathoides (Cope, 1878a "1877")
            Rio Grande Chirping Frog

J. Eric Wallace1

            The genus Syrrhophus was synonomized with the genus Eleutherodactylus and considered a subgenus (including the genus Tomodactylus) by Hedges (1989).  But Dixon (2000) notes that this synonomy does not consider behavior, morphology, or genetic characters, and so this author maintains Syrrhophus at the generic level.

1. Historical versus Current Distribution.  The type locality of Rio Grande chirping frogs (Eleutherodactylus cystignathoides) is Potrero, near Cordoba, Veracruz, Mexico (Cope, 1877).  The type locality of the subspecies found in the United States (E. c. campi) is Brownsville, Cameron County, Texas (Stejneger, 1915).  In the United States, Rio Grande chirping frogs are native to extreme south Texas along the lower Rio Grande Valley in Cameron and Hildago counties.  They have been introduced, probably by way of the potted plant trade, into Corpus Christi, Dallas, Houston, Kingsville, Tyler, San Antonio, Huntsville, and the vicinity of LaGrange, Texas (Dixon, 2000).  Some of these introduced populations have become established in the natural environment (McGown et al., 1994; Lutterschmidt and Thies, 1999).

            For information regarding this species in Mexico, see Martin (1958), Lynch (1970), and Flores-Villela (1993).  Dixon (2000) provides a current, comprehensive bibliography of Rio Grande chirping frogs.  Popular accounts in field guide format may be found in Cochran and Goin (1970), Smith and Barlowe (1978), Garrett and Barker (1987), Behler and King (1998), Conant and Collins (1998), and Bartlett and Bartlett (1999a).

            For discussions of the historical and current biogeography of the subgenus Syrrhophus (Hedges, 1989) and the species cystignathoides, see Blair (1950), Morafka (1977), and Duellman and Sweet (1999).

2. Historical versus Current Abundance.  Rio Grande chirping frogs are abundant and thrive in the presence of humans (Wright and Wright, 1949; Conant and Collins, 1998).  Brach (1992) suggests that these semi-tropical frogs are able to persist north of their native range by seeking cover under ornamental rockwork that retains heat and moisture.

3. Life History Features.

            A. Breeding.  Reproduction is terrestrial.

                        i. Breeding migrations.  Rio Grande chirping frogs do not form breeding aggregations and, as with cliff chirping frogs (E. marnockii), may maintain territories (Hayes-Odum, 1990).  Breeding occurs from April–May, when males may be heard both night and day (Wright and Wright, 1949).  Hayes-Odum (1990) found that adults called actively when the relative humidity was above 82% and when air and substrate temperatures were 16–29 ˚C.  In an introduced population in Houston, Texas, males called on rainy nights from April–July (Hayes-Odum, 1990).  Courtship behavior was observed in captivity and amplexus was axillary (Hayes-Odum, 1990).  Wright and Wright (1949) noted inguinal amplexus with captive cliff chirping frogs.

                        ii. Breeding habitat.  See "Adult Habitat" below.

            B. Eggs.

                        i. Egg deposition sites.  Eggs were laid just under the soil surface in the laboratory (Hayes-Odum, 1990). 

                        ii. Clutch size.  Eggs are laid in clutches consisting of 5–13 large eggs (3–3.5 mm in diameter; Wright and Wright, 1949; Hayes-Odum, 1990). 

            C. Direct Development.  Complete metamorphosis occurs within the egg; young hatch as froglets, ranging in size from approximately 5–8.5 mm (Wright and Wright, 1949; Hayes-Odum, 1990).  In a laboratory setting, eggs hatched after 14–16 d of artificial incubation (Hayes-Odum, 1990).

                        i. Brood sites.  Brooding has not been observed (see "Parental care" below).

                        ii. Parental care.  In a laboratory setting, Hayes-Odum (1990) observed one female leave her eggs shortly after laying them.

            D. Juvenile Habitat.  Hayes-Odum (1990) reported that hatchlings were found on wet nights.  General juvenile habitat characteristics are likely similar to adult characteristics.

            E. Adult Habitat.  Rio Grande chirping frogs inhabit low elevation coastal plains in the Tamaulipan Province (Blair, 1950).  Most published accounts of these frogs in the United States (including introduced populations) consist of observations in urban settings.  Rio Grande chirping frogs are often associated with debris piles and watered lawns and gardens (Stejneger, 1915; Wright and Wright, 1949; Hayes-Odum, 1990; Brach, 1992).  More natural environments include dense vegetation along riparian areas and the edges of lotic, semi-permanent waters (Martin, 1958; Conant and Collins, 1998).  Rio Grande chirping frogs can be found under cover objects during the day (Wright and Wright, 1949).  Brach (1992) suggests that these semi-tropical frogs are able to persist well north of their native range (e.g., Tyler, Texas) by seeking cover under ornamental rockwork that retains heat and moisture.  They are known to utilize arboreal perches 0.2–1.5 m above the ground (Martin, 1958; Hayes-Odum, 1990; Brach, 1992). 

            F. Home Range Size.  Unknown.

            G. Territories.  Hayes-Odum (1990) observed several instances of one frog moving toward another stationary frog, resulting in the displacement of the stationary frog.  From these observations, she suggested that Rio Grande chirping frogs may be territorial.

            H. Aestivation/Avoiding Dessication.  As with other members of the genus, activity diminishes with dry conditions.

            I. Seasonal Migrations.  Unknown.

            J. Torpor (Hibernation).  Unknown.

            K. Interspecific Associations/Exclusions.  Unknown, but may include (as inferred from microhabitat similarities) white-lipped frogs (Leptodactylus fragilis), marine toads (Bufo marinus), Gulf Coast toads (B. nebulifer), sheep frogs (Hypopachus variolosus), and western narrow-mouthed toads (Gastrophryne olivacea; Blair, 1950; Conant and Collins, 1998).

            L. Age/Size at Reproductive Maturity.  Rio Grande chirping frogs range in size from 15–25.5 mm SVL (Wright and Wright, 1949).  Measurements of preserved material from animals throughout their range (both subspecies) were 16.0–23.5 mm for males and 16.0–25.8 mm for females (Lynch, 1970).  The largest individual observed by Wright and Wright (1949) was a female; females tend to be larger (Hayes-Odum, 1990).  In reproductively mature females, eggs may be visible through the thin skin of their abdomen (Hayes-Odum, 1990).

            M. Longevity.  Unknown.

            N. Feeding Behavior.  Generally unknown, but one individual regurgitated cockroach eggs during capture (Wright and Wright, 1949).

            O. Predators.  Unknown.

            P. Anti-Predator Mechanisms.  To avoid capture, Rio Grande chirping frogs are quick to leap to shelter in crevices or under cover objects (Wright and Wright, 1949).

            Q. Diseases.  Unknown.

            R. Parasites.  Larval forms of Abbreviata sp. have been found in Houston populations (introduced) of Rio Grande chirping frogs (McAllister and Freed, 1992).

4. Conservation.  Rio Grande chirping frogs have no federal or state conservation status.  They are common and relatively abundant in a number of different urban settings and have been since their early discovery (e.g., Wright and Wright, 1949).  They obviously can cope with at least certain types of human-mediated habitat disturbance.  This is further evidenced by their ability to acclimate to novel habitats into which they are introduced, some very different from their native environment (e.g., Brach, 1992).

            The recent introduction of Rio Grande chirping frogs through the potted plant trade into some urban areas (e.g., San Antonio, Texas; Dixon, 2000) may place introduced frogs in direct contact with resident populations of cliff chirping frogs (E. marnockii) and other amphibians.  The repercussions of this interaction are unknown, but detrimental effects could include introduction of novel disease pathogens, competition, and/or hybridization.  Measures should be instituted to decrease the likelihood of further introductions.

1J. Eric Wallace
School of Renewable Natural Resources
University of Arizona
Tucson, Arizona 85721

Literature references for Amphibian Declines: The Conservation Status of United States Species, edited by Michael Lannoo, are here.

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