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Pictures by Chad Thomas, Texas State University - San Marcos |
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Etheostoma lepidum greenthroat darter
Type Locality Rio Leona at Uvalde, Uvalde Co., Texas (Baird and Girard 1853).
Etymology/Derivation of Scientific Name Etheostoma, from the Greek etheo, “to strain,” and stoma, mouth” (Pflieger 1997); lepidum: denotes pretty. This darter is a colorful addition to the local fauna (Kuehne and Barbour 1983).
Synonymy Beleosoma lepida Baird and Girard 1853. Oligocephalus leonensis Girard 1859. Etheostoma lepidogenys Evermann and Kendall 1894.
Characters Maximum size: 64 mm SL (Platania 1980; Kuehne and Barbour 1983).
Coloration: Color of species is geographically variable (Hubbs 1976). Throat blue or green in males (lost in preservation). 10 to 12 body bars. No black spot on upper margin of pectoral fins, no pale longitudinal streak along lateral line, and no large black rectangular blotches present on sides (Hubbs et al. 1991). Dorsum is olive; belly of male is orange, female yellow to white. 8-13 dark green-brown vertical bars along the side; bars encircle the body posteriorly, anteriorly extending ventrally only onto upper part of the belly. Interspaces between bars yellow and speckled with orange. Breast and branchiostegal membranes of male are green, those of female white. 3 vertically aligned spots at base of the caudal fin. Prominent black pre- and suborbital bars; postorbital bar reduced to a spot. In the male 1st dorsal fin has a blue-green margin, clear submarginal band, broad red-orange band, and in some areas of the species’ range a basal blue-green band. The 2nd dorsal and caudal fins have many red-brown spots arranged in concentric bands. Pelvic and anal fins mostly blue-green, often have orange or red-orange medially. Fins of the female mostly spotted with brown. Pelvic fins of both sexes clear. In breeding male, colors of fins are accentuated, breast and branchiostegal membranes bright blue-green, and bright orange blotches contrast with the dark green bars on the side of the body (Page 1983).
Counts: 50-77 lateral line scales; more than 6 pored lateral line scales; 2 anal fin spines (Hubbs et al 1991). Page (1983) lists the following counts for this species: 43-67 (48-55) lateral scales, 19-42 pored; scales above lateral line 5-7 (6); scales below lateral line 7-10; transverse scales 12-19; scales around caudal peduncle 19-25; dorsal spines 7-12 (9-10); dorsal rays 8-14 (10-12); pectoral rays 9-14 (11-12); anal rays 4-9 (6-8).
Body shape: Body cross section oval; body depth contained in standard length less than five times; head profile rounded, profile in front of eye less than 45 degrees (Hubbs et al. 1991). Rather small and slender, having a small conical head (Kuehne and Barbour 1983). Body deepest under middle of 1st dorsal fin (Page and Burr 1991).
Mouth position:
External morphology: Opercle naked or with only a few scales; infraorbital canal interrupted below eye; gill membranes barely connected; lateral line straight; pectoral fin shorter than head, not reaching anus; scales on belly normal (a narrow naked band may be present on midline); preopercle smooth or weakly serrate; upper jaw not extending as far as to below middle of eye (Hubbs et al. 1991).
Distribution (Native and Introduced) U.S. distribution: A disjunct series of populations inhabits tributaries of the Pecos River in New Mexico (Platania 1980; Hubbs et al. 1991)
Texas distribution: Inhabits Edwards Plateau streams, especially spring-influenced headwaters in the Colorado River southward to the Nueces River Basin (Hubbs et al. 1991). Warren et al. (2000) list the following drainage units for distribution of Etheostoma lepidum in the state: Colorado River, San Antonio Bay (including minor coastal drainages west of mouth of Colorado River to mouth of Nueces River), Nueces River.
Abundance/Conservation status (Federal, State, NGO) Populations in southern drainages are currently stable (Warren et al 2000). Common in Texas (Page 1983).
Habitat Associations Macrohabitat: Basically a springrun species (Hubbs 1985).
Mesohabitat: Scarce or absent from very eurythermal locations (Hubbs 1985). Occurs in a variety of non-turbid stream habitats with substrates from bedrock to silt covered (Platania 1980). A typical riffle species occurring over gravel and rubble, especially when aquatic vegetation is present. It also lives in spring areas, sometimes in cool vegetated pools (Kuehne and Barbour 1983). Largest populations occur in vegetated rocky riffles (Strawn 1955; Hubbs et al. 1953; Hubbs and Strawn 1957; Hubbs and Echelle 1972). Species benthic after hatching (Hubbs and Strawn 1957; Paine 1984).
Biology Spawning season: October or November through May, with populations in stenothermal environments having a longer spawning season than those in more eurythermal environments (Hubbs and Strawn 1957; Hubbs 1985). In the Colorado River, Texas, spawning occurs November – May (Hubbs 1961a); in the South Concho River, Texas, spawning occurs October – May (Hubbs et al. 1968). Hubbs (1985) reported marked drop in reproductive activity when water temperature was raised from 20 to 23 degrees C.
Spawning habitat: Eggs laid on vegetation (Strawn 1956), or on the underside of rocks (Hubbs and Strawn 1957).
Spawning behavior:
Fecundity: In the South Concho River, TX, eggs averaged 1.3 mm in diameter, and increased in number with female size; average number of eggs in females examined was 74, with a range of about 15-200 Hubbs et al. 1968). In aquaria, spawning was observed at approximately 15-25 degrees C; over a 63-day period, a pair of Etheostoma lepidum laid 13 batches of eggs; numbers of eggs laid ranged from 47-109, totaling 1,115 (Strawn 1956). Optimal temperature for egg production apparently 20-23 degrees C; a female held at this temperature range was observed to produce eggs, in the laboratory environment, over a period of at least 251 days (Hubbs and Strawn 1957). Egg incubation success is low above 24 degrees C (Hubbs 1961a; Hubbs et al. 1969). At 28 degrees C, eggs hatch in 4-5 days, and hatch in about 40 days at 9 degrees C (Hubbs 1961b). Hubbs (1985) noted that no difference in egg production could be correlated with daylength.
Age at maturation:
Migration:
Longevity:
Food habits:
Growth:
Phylogeny and morphologically similar fishes It is easily confused with the orangethroat darter (Etheostoma spectabile), which has a less developed banding on the caudal peduncle; also, the lateral line is almost complete in E. lepidum (Kuehne and Barbour 1983). Female hybrids of E. lepidum X E. spectabile are fertile; males are sterile (Hubbs 1958). Most closely related to allopatric Rio Grande darter (E. grahami) of lower Pecos River and closely adjacent area (Platania 1980); E. grahami is deeper bodied; has many small red (on male) or black (on female) spots on side of body, red edge on 1st dorsal fin (Page and Burr 1991).
Host Records
Commercial or Environmental Importance Hubbs and Echelle (1972) reported water supply and habitat problems leading to decline in distribution. Species in no immediate danger of extirpation; however, some populations are in a precarious position (Kuehne and Barbour 1983).
[Additional literature noting collection of this species from Texas locations includes, but is not limited to the following: Hubbs (1957); Hubbs and Hettler (1958); Hubbs (1960); Hubbs and Martin (1965); Hubbs 1967).]
References
Baird, S.F. and C. Girard. 1853. Descriptions of New Species of Fishes collected by Mr. John H. Clark, on the U. S. and Mexican Boundary Survey, under Lt. Col. Jas. D. Graham. Proceedings of the Academy of Natural Sciences of Philadelphia 6(7): 387-390.
Evermann, B.W., and W.C. Kendall. 1894. The fishes of Texas and the Rio Grande basin, considered chiefly with reference to their geographic distribution. Bull. U.S. Fish Comm. 57-126.
Girard, C.F. 1859. Ichthyological notices. Proc. Acad. Nat. Sci. Phila. 11:100-104.
Hubbs, C. 1957. Distributional patterns of Texas fresh-water fishes. The Southwestern Naturalist 2(2/3):89-104.
Hubbs, C. 1958. Fertility of Fı hybrids between the percid fishes, Etheostoma spectabile and E. lepidum. Copeia 1958:57-59.
Hubbs, C. 1960. Duration of sperm function in the percid fishes Etheostoma lepidum and E. spectabile, associated with sympatry of the parental populations. Copeia 1960(1):1-8.
Hubbs, C. 1961a. Developmental temperature tolerance of four etheostomatine fishes occurring in Texas. Copeia 1961:195-198.
Hubbs, C. 1961b. Differences in the incubation period of two populations of Etheostoma lepidum. Copeia 1961:198-200.
Hubbs, C. 1967. Geographic variations in survival of hybrids between Etheostomatine fishes. Bulletin of the Texas Memorial Museum 13:1-72.
Hubbs, C. 1976. A checklist of Texas freshwater fishes. Rev. ed. Tech. Ser. Tex. Parks Wildl. Dep. 11. 12 pp.
Hubbs, C. 1985. Darter reproductive seasons. Copeia 1985(1):56-68. Hubbs, C., and A.A. Echelle. 1972. Endangered non-game fishes of the upper Rio Grande basin pp. 147-167. In: Rare and endangered wildlife of Southwestern Unites States. New Mexico Game and Fish Dept., Santa Fe. Hubbs, C., and K. Strawn. 1957. The effects of light and temperature on the fecundity of the greenthroat darter, Etheostoma lepidum. Ecology 38:596-602. Hubbs, C., and P.S. Martin. 1965. Effects of darkness on egg deposition by Etheostoma lepidum females. The Southwestern Naturalist 10(4):302-306. Hubbs, C., and W.F. Hettler. 1958. Flutuations of some central Texas fish populations. The Southwestern Naturalist 3(1/4):13-16.
Hubbs, C., R J. Edwards, and G.P. Garrett. 1991. An annotated checklist of the freshwater fishes of Texas, with keys to identification of species. Texas Journal of Science, Supplement 43(4):1-56.
Hubbs, C., R.A. Kuehne, and J.C. Ball. 1953. The fishes of the upper Guadalupe River. Texas Journal of Science 5(2):216-244.
Hubbs, C., A.E. Peden, and M.M. Stevenson. 1969. The developmental rate of the greenthroat darter, Etheostoma lepidum. Amer. Midl. Nat. 81:182-188.
Hubbs, C., M.M. Stevenson, and A.E. Peden. 1968. Fecundity and egg size in two central Texas darter populations. Southwestern Naturalist 13:301-323.
Kuehne, R.A., and R.W. Barbour. 1983. The American Darters. The University Press of Kentucky. Lexington. 177 pp.
Page, L.M. 1983. Handbook of Darters. T.F.H. Publications, Inc., Ltd., Neptune City, NJ. 271 pp. Page, L.M., and B.M. Burr. 1991. A Field Guide to Freshwater Fishes: North America, north of Mexico. Houghton Mifflin Company, Boston, Massachusetts. 432 pp.
Paine, M.D. 1984. Ecological and evolutionary consequences of early ontogenies of darter (Etheostomatini). pp. 21-30. In: Lindquist, D.G., and L.M. Page (eds.), Environmental Biology of Darters. Dr W Junk Publishers, The Hague.
Pflieger, W.L. 1997. The Fishes of Missouri. Missouri Department of Conservation, Jefferson City. 372 pp. Platania, S.P. 1980. Etheostoma lepidum (Baird and Girard), Greenthroat darter. pp. 661 in D. S. Lee et al., Atlas of North American Freshwater Fishes. N. C. State Mus. Nat. Hist., Raleigh, i-r+854 pp.
Strawn, K. 1955. A method of breeding and raising three Texas darters. Part I. Aquarium Journal 26:408-412.
Strawn, K. 1956. A method of breeding and raising three Texas darters. Part II. Aquarium Journal 27(1):11-32. Warren, M.L., Jr., B.M. Burr, S.J. Walsh, H.L. Bart, Jr., R.C. Cashner, D.A. Etnier, B.J. Freeman, B.R. Kuhajda, R.L. Mayden, H.W. Robison, S.T. Ross, and W.C. Starnes. 2000. Diversity, Distribution, and Conservation status of the native freshwater fishes of the southern United States. Fisheries 25(10):7-29.
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