“It was a startling and grotesque spectacle to observe this squatting monster slowly and motionlessly take form where apparently there had been nothing before upon the oozy bottom.” - William Ray Allen, 1922
Telmatobius culeus is entirely aquatic. This species ranges in size from approximately 76 to 140mm (snout-vent length) (Garman 1876; Hutchison et al. 1976), with a weight up to 250g (Hutchison et al 1976). Telmatobius culeus has a distinctive wide and flat body with baggy skin folds hanging from the dorsum, sides, and hind legs (Garman 1876; Hutchison et al. 1976). In accord with its aquatic nature, the lungs in this frog are markedly reduced in size compared to ranids of similar size (Allen 1922; Hutchison et al. 1976). Telmatobius culeus displays physiological, behavioral, and morphological specializations that may be adaptations to aquatic life at a high altitude (Navas 2006; Hutchison et al. 1976; Trueb 1979).
Telmatobius culeus is a large, completely aquatic frog (74.82 mm to 137.95 mm SVL). This frog has a large flat head with a round snout, a thick, well-developed dorsal disc, and prominent skin folds (Benavides et al. 2002). Lungs are greatly reduced and are less than one-third the size that would be expected for a ranid frog of the same body size (Allen 1922). T. culeus respires primarily through its skin and has many large vascularized skin folds on the dorsum, sides and hind limbs as well as a highly vascularized buccal cavity (Macedo 1960). The skin folds essentially serve as gills for these animals (Hutchison et al. 1976).
This species was first described by Garman (1876). See Benavides et al. (2002) for a discussion of species boundaries among Lake Titicaca species of Telmatobius, using allozyme data and multivariate morphometrics; there are different morphs along a depth gradient (similar to the situation in some freshwater fish species) but all are now considered T. culeus. Sinsch et al. (1995), using multivariate morphometric assessments, had previously concluded that a number of purported subspecies were all junior synonyms of T. culeus. See also Benavides (2005); this study was not able to distinguish between T. culeus and T. marmoratus from the Lake Titicaca drainage, using mtDNA.
Distribution and Habitat
T. culeus is distributed in a region that spans the border between Bolivia and Peru. It is found within Lake Titicaca and in rivers flowing into the lake, as well as in small ponds about 70 km away, near Lago Saracocha (Benavides et al. 2002). In addition, a single specimen has been reported from a lower-elevation locality (2,500 m asl) about 200 km east of Lake Titicaca, in warm springs near the Rio Yura (Benavides et al. 2002).
The elevation of Lake Titicaca is 3,812 m and it reaches a maximum depth of 281 m (Hutchison et al. 1976). Water temperature average is 10°C at both the surface and the bottom; surface waters fluctuate slightly but the annual fluctuation is less than 4°C (Hutchison et al. 1976). The water is saturated with oxygen because of the high winds and wave action (Hutchison et al. 1976).
Telmatobius culeus is found exclusively in the Lake Titicaca basin, on the border of Peru and Bolivia, altitude 3812 m. Found on the eastern coast of Lake Titicaca and into the connected Lago Pequeño (Benavides et al. 2002; Benavides 2005; Vellard 1992; de la Riva et al. 2010). The species is absent from shallow portions of the southern portion of the lake and from Laguna Arapa and Bahía de Puno in the northern basin (Benavides et al. 2002).
General note: As is characteristic of the genus, Telmatobius culeus displays high variability in morphological characters including size, color, external morphology, and even osteology (Benavides 2005). This may be due to considerable phenotypic plasticity in the species. There may be different ecotypes of the species: for instance, one consisting of large frogs found in the deep water and one of small bodied forms that develop more quickly and live in shallower water (Benavides et al. 2002).
Color: Telmatobius culeus has variable coloration ranging from uniform olive brown to brown with white spots. Some have many white spots, such that they appear grey (Garman 1876). Black spots and patches are sometimes present. One depicted individual has black spots over entire dorsal surface (ventrum not shown) (Vellard 1992). The ventral surface of the Lake Titicaca frog ranges from light grey in some populations to bright orange (in the southern ‘T. albiventris’ population) (Vellard 1992). Body color in this species has also been described as dark green (Fontúrbel 2004).
External appearance: The Lake Titicaca Frog has a dorsoventrally compressed (flattened) body and head, with its head nearly as wide as its trunk (Vellard 1992). A prominent feature in this species is baggy skin on the dorsum, sides and the hind legs. In larger individuals there are bilateral dorsolateral folds running from the eye to the groin, creating a large dorsal disc of skin (Parker 1940). This skin may be filled with fluid in life, approximately doubling the animal’s volume (Vellard 1992). Telmatobius culeus has un-webbed fingers, with partially-webbed toes. The tympanum is not visible. In some individuals vomerine teeth are present in two small groups, or on one side only (Garman 1876), but often do not penetrate the oral mucosa (Parker 1940). Telmatobius culeus has a short tongue, which is free posteriorly (Allen 1922). Its skin can be smooth or warty. There is no vocal sac present (Garman 1876).
Body size: Adults are over 130 mm long (snout-vent length) (Vellard 1992), and up to 140 mm (Hutchison et al. 1976). Parker (1940) states a maximum length of 115-134 mm, considering males and females. There may be sexual dimorphism in body size, with the average female length 97.2 mm (N = 17) and an average length in males of 85.2 mm (N = 20) (Parker 1940). Weight in this species can reach 250g (Hutchison et al 1976). The animal may grow much larger than these reported values. Pough et al. (2004) report lengths of up to 250 mm.
Viscera: One of the key features of the internal anatomy of T. culeus is the drastic reduction in the size of the lungs to approximately one third of the size of a ranid frog of equivalent body size (Hutchison et al. 1976; Allen 1922). The lungs have primary alveoli only, likely limiting their respiratory capacity. The lungs do function to some extent—when placed in hypoxic water T. culeus can maintain its metabolic rate using pulmonary respiration alone for several hours (Hutchison et al 1976). Cutaneous respiration likely makes up for reduced pulmonary respiratory capacity. The Lake Titicaca Frog’s skin is highly vascularized, with capillaries nearly reaching the outermost layers of the epidermis (Hutchison et al. 1976). The network of relatively large capillaries is more intricate and extensive than most frogs, according to Allen (1922).
Skeleton: Telmatobius culeus has a less ossified skeleton than T. marmoratus. The skull is “thin and shell-like” with larger cranial fenestrae and fontanel than T. marmoratus (Garman 1876).
Ontogenetic changes: The extent of toe webbing increases with age (Parker 1940). Juveniles do not display skin bagginess and cannot be distinguished from T. marmoratus (Parker 1940). The requirement for baggy skin would presumably increase as the animal grows, since the surface area to volume ratio would decrease with increasing body volume.
Habitat and Ecology
Telmatobius dwells on the lake bottom and never leaves the water (Hutchison et al. 1976). The frog may be present up to the maximum depth of over 280 m, as evidenced by their presence in fishing nets pulled along the lake bottom (Hutchison et al. 1976).
The high altitude of Lake Titicaca presents several challenges to amphibians, including low temperature (10°C on average), low partial pressure of oxygen, and high solar radiation. Oxygen solubility at this altitude and temperature (10°C) is approximately 65% of what it would be at sea level (Northcote 1992).
Life History and Behavior
Behavior: Under natural conditions the animal has not been observed surfacing to breath air. Allen (1922) claimed that it was typically observed on the lake bottom and never found out of water. Authors have frequently commented on its sedentary nature (Garman 1876, Allen 1922). When oxygen in the water is experimentally reduced, the frogs will move to the surface and place their nostrils above water to ventilate their lungs. Telmatobius culeus will remain in this position until the dissolved oxygen content increases to an acceptable level (Hutchison et al. 1976). If the animal is prevented from reaching the surface under hypoxic conditions they will remain on the bottom and stand with limbs and digits extended (presumably to maximize surface area exposed to water). The frog will then bob vigorously approximately every six seconds by pushing up with its hindlimbs until its entire body lifts off of the substrate. It will then slowly sink back to the bottom (Hutchison et al 1976). This motion causes the skin flaps to wave back and forth, likely breaking up or minimizing the boundary layer of oxygen-depleted water surrounding the animal (Hutchison et al. 1976; Pinder and Feder 1990). This rocking behavior is similar to that seen in Cryptobranchus alleganiensis (Hutchison et al. 1976).
Diet: Telmatobius culeus eats aquatic animals including tadpoles, fish, mollusks, and crustaceans (Allen 1922; Garman 1876). Allen (1922) reported finding a 100mm long fish in the stomach of one individual.
Auditory communication: There is no published data on auditory communication in T culeus. The absence of a vocal sac and its aquatic habitat indicates that they do not call. The lack of auditory signals may be characteristic of the genus (Trueb 1979).
Defense behavior: This species will secrete a milky mucous when handled or harassed (Allen 1922).
Predators: Telmatobius is preyed upon by fish. Garman (1876) proposed that birds prey on the species, but Allen (1922) failed to confirm this.
Life history: Telmatobius culeus reaches reproductive maturity at two years. They spawn in the stems of Schoenoplectus californicus spp. (California bulrush) (Perez 1998, cited in Fontúrbel 2004).
Reproduction and life history: There is little published data available on reproduction in this species. M.E. Perez (1998) reported approximately 500 eggs per clutch in an unpublished thesis (cited by Barrionuevo and Ponssa 2008).
Evolution and Systematics
Numerous subspecies of Telmatobius culeus have been described based on morphological differences (de la Riva et al 2000). High phenotypic plasticity makes morphological taxonomies unreliable, even when based on osteological characters (de la Riva et al 2010). The most recent analysis based on sequenced mtDNA places T. culeus as a sister taxon to T. marmoratus (de la Riva et al 2010). Although a phylogenetic study using morphometrics and allozyme data did support reciprocal monophyly of these groups (Benavides et al 2002), a different result was obtained by sequencing mitochondrial cytochrome b (Benavides 2005). Benavides (2005) failed to support monophyletic clades for T. marmoratus and T. culeus, and instead found support for separate riverine and lacustrine clades. These discrepancies may be resolved in the future by sequencing nuclear genes from a wider sample of T. culeus.
Frost et al (2006) placed the Telmatobius genus within the family Ceratophryidae (subfamily Telmatobiinae) instead of within Leptodactylidae.
Phylogenetic studies have also addressed the degree of phenotypic plasticity in this species. Benavides et al. (2002) synonymized several of the subspecies of T. culeus. The implication of this work is that highly divergent ecotypes of T. culeus exist. These ecotypes show divergent resource use and morphology, indicating that the species has a high degree of phenotypic plasticity (especially in terms of body size) and niche polymorphism.
Physiology and Cell Biology
The Lake Titicaca Frog has numerous physiological adaptations to its low oxygen aquatic environment. It has a higher red blood cell count than any other reported frog (Hutchison et al. 1976). Telmatobius culeus has the second smallest erythrocyte volume of any amphibian (Telmatobius pefauri is the smallest, Ruiz et al. 1983). Small erythrocytes facilitate the flow of oxygen from the environment to the cells (Ruiz et al. 1983). The metabolic rate of T. culeus is lower than any frog measured when submerged or when breathing air (14.1 ml O2 * g -1 * h-1 at 10°C underwater and at low altitude and 23.1 ml O2 * g -1 * h-1 at 10°C breathing air and at low altitude) (Hutchison et al 1976). The metabolic efficiency and respiratory adaptations of T. culeus allow it to survive highly hypoxic conditions for several hours. However, some of these traits are affected by acclimatization to lower elevations, which indicates that they are at least partially plastic.
Molecular Biology and Genetics
Statistics of barcoding coverage: Telmatobius culeus
Public Records: 0
Specimens with Barcodes: 1
Species With Barcodes: 1
IUCN Red List Assessment
Red List Category
Red List Criteria
Life History, Abundance, Activity, and Special Behaviors
This frog is fully aquatic (Allen 1922). Although it seems to prefer the bottom of the lake, it occurs throughout the water column and has been observed on rock ledges within two feet of the water surface (Hutchison et al. 1976). It does not surface for air if the water is well-oxygenated, although dissections have shown small amounts of gas in the lungs (Hutchison et al. 1976). T. culeus is able to effectively remove oxygen from water with its skin (Hutchison et al. 1976). Lungs are reduced and poorly vascularized; respiration appears to take place primarily through the large and highly vascularized skin folds hanging from the dorsum, sides and hind limbs (Macedo 1960). Other adaptations for aquatic life at high altitude include one of the highest red blood cell (RBC) counts reported for any anuran (see Ruiz et al. 1983 for a comparison), one of the smallest red blood cell volumes reported for any anuran (see Ruiz et al. 1983 for comparisons between species), a relatively high oxygen capacity, and a relatively high hemoglobin content (Hutchison et al. 1976). Under hypoxic conditions, the frog will surface; if it is prevented from surfacing, it does not struggle but stands on the bottom with legs and toes extended to maximize skin surface exposure to the water, and will bob up and down about once every six seconds (Hutchison et al. 1976). This acts to move the large skin flaps, which breaks up the boundary layer between the skin and the water, allowing the skin to more fully absorb the limited oxygen from the water (Hutchison et al. 1976).
This species has the lowest reported metabolic rate (14.1 microliters/gram-hour) under non-hypoxic conditions for any frog, and one of the lowest among all amphibians; only a few salamander genera have lower metabolic rates (Hutchison et al. 1976). This rate is likely to be an overestimate, as it was measured at low altitude in captive frogs and not at the elevation of the natural habitat in Lake Titicaca (Hutchison et al. 1976). An extremely low metabolic rate is likely to be the case for other species in the genus Telmatobius as well (see Ruiz et al. 1983).
Breeding takes place near the shoreline in shallow waters (Stuart et al. 2008). The clutch size is about 500 eggs (Pérez 1996).
Under the stress of being held, T. culeus secretes copious quantities of a sticky, milky secretion; Allen (1922) reports that the skin creases "become filled with it."
Diet includes amphipods, snails, aquatic insects, tadpoles, and fish; stomach contents of one T. culeus were found to include a four-inch-long fish of the genus Orestias (Allen 1922).
Life History, Abundance, Activity, and Special Behaviors
It was once common, but due to massive population declines (more than 80% over the past fifteen years), Telmatobius culeus is now critically endangered (Benavides et al. 2002). Captive-breeding programs have so far not been successful (Perez Bejar 2005). Although its habitat lies within the Lake Titicaca Reserve, threats include overcollection, introduced trout, lake water extraction, water pollution, and loss of breeding habitat (Stuart et al. 2008). It is not known whether T. culeus is susceptible to chytridiomycosis, but this disease also presents a potential threat (Stuart et al. 2008); it has been speculated that all three Ecuadorian species of Telmatobius have been extirpated by chytridiomycosis (Merino-Viteri et al. 2005), and chytrid infections of Peruvian T. marmoratus have been reported (Seimon et al. 2005; Seimon et al. 2007), as well as Argentinian T. pisanoi (Barrionuevo and Ponssa 2008). Telmatobius species share traits common to amphibian species with higher susceptibility to chytridiomycosis: high altitude distributions, low fecundity, strongly aquatic, and specialized habitat (Barrionuevo and Ponssa 2008).
Telmatobius culeus faces several anthropogenic affronts, including commercial harvesting and habitat degradation (Fontúrbel 2004). Telmatobius culeus has experienced massive declines recently, estimated to be over 80% in the last 15 yrs (approximately 3 generations) (Ichochea et al 2004). There is a scarcity of published data on population size and/or declines. The principal threat to the species is overharvesting of adults. In spite of Allen’s (1922) assessment that the local people do not consume the frogs, this species is currently harvested in large quantities for consumption both locally and abroad (Fontúrbel 2004; Icochea et al. 2004). The IUCN lists this species as critically endangered (CR).
The plant Schoenoplectus californicus, around which the species spawns, is increasingly harvested to feed livestock. Pollution from nearby communities and agriculture has caused eutrophication of the lake and reduction in dissolved oxygen levels (Fontúrbel 2004, Northcote 1992). Chytridiomycosis has not been reported in this species, though it remains a threat (Icochea et al. 2004). Seimon et al. (2005) documented chytridiomycosis in Telmatobius marmoratus, which is often closely associated with T. culeus.
Relevance to Humans and Ecosystems
Relation to Humans
At one time it was thought the frog's thick, sticky white secretion, which is exuded under stress, may render it unpalatable (Hutchison et al. 1976). Currently, one of the reasons for overharvesting of adults of T. culeus is for consuming as an aphrodisiac, especially on the Peruvian side of the lake (A. Catenazzi, pers.comm.).
Telmatobius culeus, commonly known as the Titicaca water frog, is a very large and critically endangered species of frog in the Leptodactylidae family. It is entirely aquatic and only found in Lake Titicaca and rivers that flow into this lake in South America. While the lungs are greatly reduced, this frog has excessive amounts of skin, used to help the frog respire in the high altitude in which it lives.
In the early 1970s, an expedition led by Jacques Cousteau reported frogs up to 50 centimetres (20 in) in outstretched length, with individuals commonly weighing 1 kilogram (2.2 lb), making these some of the largest exclusively aquatic frogs in the world (the fully aquatic Batrachophrynus macrostomus is larger, as is the African goliath frog, which sometimes can be seen on land). The snout-vent length is 7.5–13.8 centimetres (3.0–5.4 in).
Once common, the Titicaca water frog has declined drastically and is now facing extinction due to over-collecting for human consumption, pollution, and predation of tadpoles by introduced trout. It may also be threatened by the disease chytridiomycosis. Several other species in the genus Telmatobius are facing similar risks.
- Javier Icochea, Steffen Reichle, Ignacio De la Riva, Ulrich Sinsch, Jörn Köhler (2004). "Telmatobius culeus". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 18 March 2014.
- Stuart, Hoffmann, Chanson, Cox, Berridge, Ramani and Young, editors (2008). Threatened Amphibians of the World. ISBN 978-84-96553-41-5
- 2004, Amphibiaweb, IUCN, Conservation International, and NatureServe
- Victoria Gill (12 September 2013). "Blobfish wins ugliest animal vote". BBC News. Retrieved 12 September 2013.
To request an improvement, please leave a comment on the page. Thank you!