© 2010 Stephen Bennett (1 of 11)
Can you confirm these amateur observations of Siren lacertina?
Siren lacertina Linnaeus, 1766
1. Historical versus Current Distribution. Greater sirens (Siren lacertina) are found in the Atlantic and Gulf Coastal Plains from eastern Virginia (Burch and Wood, 1955) through extreme south Florida, west to southwestern Alabama (Conant and Collins, 1998; Petranka, 1998). A disjunct population occurs in the Rio Grande valley of northern Mexico and southern Texas (Flores-Villela and Brandon, 1992), although Petranka (1998) believes that further genetic characterization is needed to determine the status of sirens in Texas (see Siren texana account, this volume). Their historical distribution (Barton, 1808) is most likely similar to current distribution.
2. Historical versus Current Abundance. Abundance from the 1960s to the present is not well documented in the literature, except for Florida, southeastern Georgia, and eastern South Carolina (Petranka, 1998) where greater sirens are considered common. Historically, greater sirens have been considered common in the southeastern United States (Barton, 1808; Jobson, 1940; Neill, 1949b), including Florida (Bishop, 1943). In the periphery of their range they are considered Locally Abundant to Rare (Burch and Wood, 1955; Martof, 1956a).
3. Life History Features.
i. Breeding migrations. In Gainesville, Florida, mature greater sirens move into shallow water or streams to congregate for breeding in February–March (Ultsch, 1973).
ii. Breeding habitat. In shallow water or streams (Ultsch, 1973).
i. Egg deposition sites. In Gainesville, Florida, eggs were found in 15-cm-deep water of a shallow ditch, 1 m from shore in a macrophyte bed predominated by Myriophyllum sp. (Goin, 1947c). Little else is known of nest site selection (Petranka, 1998).
ii. Clutch size. Captive females lay eggs singly or in small groups (Ultsch, 1973) that total around 500 eggs (Noble and Marshall, 1932). Nests may be guarded by females (Ultsch, 1973).
i. Length of larval stage. Unknown.
ii. Larval requirements.
a. Food. Unknown, although juveniles are reported to feed on small invertebrates (Petranka, 1998).
b. Cover. Young greater sirens are often seen amid water hyacinth roots (Martof, 1973) or other heavy vegetation (Petranka, 1998).
iii. Larval polymorphisms. None reported.
iv. Time to metamorphosis. Difficult to determine. During the first year of life, larval striping is reduced, then lost; juveniles are variously mottled (Duelmann and Schwartz, 1958; see also Petranka, 1998).
v. Post-metamorphic migrations. Do not occur in the usual sense. As greater sirens mature, they are found in increasingly deeper waters (Duelmann and Schwartz, 1958; see also Petranka, 1998).
vi. Neoteny. Called the “most larval” of all salamanders (Noble, 1927b), sirens have external gills and lack hind feet. However, the skin undergoes metamorphosis (Martof, 1974).
D. Juvenile Habitat. Similar to larval and adult characteristics.
E. Adult Habitat. Greater sirens are found in muddy and weed-choked ditches (Funderburg and Lee, 1967), swamps, and ponds (Jobson, 1940; Neill, 1949b), as well as large lakes and streams. No differences have been reported regarding habitats of males versus females.
F. Home Range Size. Unknown.
G. Territories. Unknown.
H. Aestivation/Avoiding Dessication. When faced with desiccating conditions, greater sirens burrow into the muddy bottom (Freeman, 1958). A cocoon comprised of primarily dead squamous epithelial cells is produced to retard water loss (Etheridge, 1990b), and the gills rapidly atrophy (Noble, 1927b). A lab-starved specimen from Georgia survived 5.2 yr and lost 86.5% of its original weight before dying. Recovery from aestivation under suitable conditions is likely rapid (Martof, 1969).
I. Seasonal Migrations. No information exists directly regarding seasonal migrations. However, greater sirens in Florida are able to surmount a 46-cm (18-in) high dam with ease (Bishop, 1943). It is reported that greater sirens have the ability to leave water voluntarily (Osterdam, 1769; Barton, 1808; Harlan, 1826b), although this habit has not been noted by more contemporary authors.
J. Torpor (Hibernation). Torpor has not been observed, but feeding activity has been shown to decrease with colder water temperatures in Alabama (Hanlin and Mount, 1978).
K. Interspecific Associations/Exclusions. In Polk County, Florida, greater sirens were found in association with two-toed amphiumas (Amphiuma means), peninsula newts (Notophthalmus viridescens piarpicola), and lesser sirens (Siren intermedia; Funderburg and Lee, 1967).
L. Age/Size at Reproductive Maturity. Unknown.
M. Longevity. One captive greater siren was reported to live 25 yr (Flower, 1936). Another, housed at the Cincinnati Zoo, lived almost 15 yr (Snider and Bowler, 1992).
N. Feeding Behavior. Primarily nocturnal (Hanlin and Mount, 1978) and carnivorous, although algae found in the digestive tracts of sirens has led some to believe that they may be omnivorous (Dunn, 1924; Ultsch, 1973; Hanlin, 1978). Able to filter feed from bottom debris (Hanlin, 1978) and also feed opportunistically (Hanlin and Mount, 1978). Prey include insects, crustaceans (Duellmann and Schwartz, 1958), gastropods, pelicypods, spiders, mollusks (Hanlin, 1978), crayfish, gastroliths, and small fish (Moler, 1994). Burch and Wood (Ultsch, 1973, 1955) suggest that opportunistic feeding may be accomplished by use of the Jacobsen’s organ rather than vision due to the low water clarity that often exists in the habitats of greater sirens.
O. Predators. Information is scant regarding predators, however, greater sirens have been found in the stomachs of red-bellied mud snakes (Farancia abacura; Van Hyning, 1932) and American alligators (Alligator mississippiensis; Delany and Abercrombie, 1986).
P. Anti-Predator Mechanisms. A variety of noises have been attributed to the greater siren, which may function as a defense mechanism or may be involuntary (Maslin, 1950). Noises include yelping, a sound similar to green treefrogs (Hyla cinerea) from a distance (Conant and Collins, 1998), hissing (Barton, 1808), croaking (Ellis, 1767), and a sound like that of young ducks (Osterdam, 1769). Noble and Marshall (1932) reported that greater sirens can escape disturbance by swimming away rapidly, while Oliver (1955a) states that sirens can produce a painful bite.
Q. Diseases. The only reference to disease is from a captive specimen that died from an infection of Saprolegnia sp. fungus (Goin, 1961).
R. Parasites. Platyhelminth parasites, including trematodes, cestodes, and nematodes, have been recorded in Florida, as summarized in McAllister et al. (1994).
4. Conservation. Greater sirens have been considered common in the more central portions of their range, and from locally abundant to rare in more peripheral sites. In Maryland, one peripheral area, they are listed as Endandered/Extirpated and afforded legal protection (Levell, 1997). One problem with permanently aquatic salamanders is that populations are difficult to monitor. States that harbor these animals should consider long-term monitoring programs.
Literature references for Amphibian Declines: The Conservation Status of United States Species, edited by Michael Lannoo, are here.
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