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Las Vegas Valley Leopard Frog

Lithobates fisheri (Stejneger 1893)

Comprehensive Description

    Description
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    Males 44-64 mm SVL; females 46-74 mm SVL (Wright and Wright 1949). This species resembles Rana pipiens and Rana onca; R. fisheri can be distinguished by more reduced dorsal/head spotting and shorter legs than R. onca, which in turn has smaller and fewer spots and shorter legs than R. pipiens (Linsdale 1940).

    Heel of extended hind limb falls considerably short of snout tip (Stejneger 1893). Tympanic disc has vertical diameter greater than the distance between the nostrils and eye (Stejneger 1893). Vomerine teeth between choanae and projecting beyond choanae posteriorly (Stejneger 1893). Hind feet about 2/3 webbed (Stejneger 1893). Single small metatarsal tubercle (Stejneger 1893). Paired weak dorsolateral ridges, and lacking longitudinal folds between the dorsolateral ridges (Stejneger 1893). Skin is granular on posterior lower aspect of femur (Stejneger 1893). Dorsum and flanks with numerous small dark spots "surrounded by lighter" (Stejneger 1893). No black ear patch (Stejneger 1893). Although Stejneger (1893) stated that external vocal sacs were not present, Wright and Wright (1949) report the presence of vocal sacs both from field experience with live frogs and from preserved specimens.

    Olive green ground color, sometimes with the anterior body a brighter green, and with dark greenish olive to green spots. Spots often reduced or indistinct on anterior body/head, especially in males. Light stripes along dorsolateral folds. Throat light green with some pinkish suffusion, clouded with dark grayish olive green. Chest and belly may have pinkish cinnamon and may be clouded like the throat. Ventral surfaces of hindlimbs honey yellow to chamois. Males have nuptial pads. Females have more spotting dorsally than males (Wright and Wright 1949, from 1925 field notes on Tule Springs specimens, collected about 16 miles from what was Las Vegas at the time). Linsdale (1940) notes that R. fisheri had a "peculiar shade of ground color" compared to R. pipiens, but the shade is not otherwise described by that author.

    Holotype USNM 18957 (adult female) was collected on March 13, 1891 (Jennings 1988). Specimens collected at Vegas Valley in 1891 are at USNM (HerpNET); specimens are also present in the MVZ, Stanford and California Academy of Sciences collections (Wright and Wright 1949), and at LACM (HerpNET).

    This taxon has been treated as Rana fisheri (Stejneger 1893; Jennings et al. 1995) and as synonymous with (Slevin 1928) or a subspecies of R. onca (Jennings 1988; Stebbins 2003). Linsdale (1940) and Jennings et al. (1995) suggested on the basis of morphological analysis that R. fisheri was in fact a distinct species and not a subspecies of R. onca.

    Hillis and Wilcox (2005) also noted that populations of leopard frogs (characterized as R. chiricahuensis) from the Mogollon Rim, Arizona, may be referrable to R. fisheri, based on morphological similarity.

    In 2011, Hekkala and colleagues used ancient DNA methods with frogs fixed in ethanol in 1915 and preserved at the California Academy of Sciences to show that samples of R. fisheri cluster within the northwestern clade (of two clades currently assigned to Rana chiricahuensis), and they have assigned members of that clade (mainly from the Mogollon Rim region) to R. fisheri. The status of the second clade, currently R. chiricahuensis, is now in question, especially important given recent focus on conservation efforts.

Distribution

    Distribution and Habitat
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    Rana fisheri was known from several localities in the northern Las Vegas Valley, Clark County, Nevada, USA, at elevations of about 600 m. This species was associated with springs and trickling streams in "springy fields", with the habitat isolated by the surrounding desert (Wright and Wright 1949). It was reported to be sympatric with Pseudacris regilla and Bufo compactilis at what was Tule Springs in 1925 (Wright and Wright 1949).

Trends

    Life History, Abundance, Activity, and Special Behaviors
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    This species was last documented prior to 1942 and it is now presumed to be extinct (Jennings et al. 1995; Stuart et al. 2008). Two specimens in the LACM collection were obtained from Tule Springs in 1941 (HerpNET). By the following year (1942) the habitat at Tule Springs had clearly been altered by urbanization; during searches in May 1942 (see below), splashes were heard near tules, thought to be from R. fisheri leaping into the water, but frogs were not seen (Wright and Wright 1949).

    In field notes (MVZ) from 1942, Wright and Wright (1949) say:

    "May 16. What frog hunters we are! I thought I was good at it. I came here once with a golden spoon in my mouth. Seventeen years have gone since we were here last. Las Vegas has grown, but how? Thirty-five men sleeping on the Union Pacific lawn. Roads are changed. Took us most of the day to locate where the old artesian well and the springs were. At the U. S. Fish Hatchery found bullfrogs. The municipal golf course and possibly the hatcheries are where the springs were. Looked these over but no R. fisheri. Tried Las Vegas Creek upper stretches. Found a minnow and plenty of crayfish but no frogs.

    May 17. Went out Main Ave. to U. S. Fish Hatchery. Looked around the big pond. No frogs. Walked from municipal golf course along water to main Tonopah road. Heard one jump in tules, probably my game. Went to Fifth St. crossing of Las Vegas Creek. Looked it over. West of this crossing in tules heard one splash of frogs. Never saw them. This afternoon at 4:30 went to Main Street crossing and walked up to old artesian well, a mile or so. Some minnows in stream, lots of crayfish-heard four splashes in tules but never saw frogs. What a state! Men sleeping under trees, unemployed, unhoused, and some unclean, one group quarreling.

    Our R. fisheri may go with the old springs gone, the creek a mess."

Threats

    Life History, Abundance, Activity, and Special Behaviors
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    Habitat loss is probably the main factor that led to this species' demise, from depletion of spring water and ground water as the city of Las Vegas expanded. It is likely that competition with introduced Rana catesbeiana also contributed to the extinction of Rana fisheri. Only Rana catesbeiana were seen in May 1942 near the original site; a few splashes were heard that were thought to be R. fisheri but none were seen (Wright and Wright 1949). Introduced crayfish and game fish may also have contributed (Jennings and Hayes 1994).