W&M ScholarWorks VIMS Articles 1982 Larval Development Of Citharichthys-Cornutus, Citharichthys- Gymnorhinus, Citharichthys-Spilopterus, And Etropus-Crossotus (Bothidae), With Notes On Larval Occurrence John W. Tucker Jr. Virginia Institute of Marine Science Follow this and additional works at: https://scholarworks.wm.edu/vimsarticles Part of the Aquaculture and Fisheries Commons Recommended Citation Tucker, John W. Jr., "Larval Development Of Citharichthys-Cornutus, Citharichthys-Gymnorhinus, Citharichthys-Spilopterus, And Etropus-Crossotus (Bothidae), With Notes On Larval Occurrence" (1982). VIMS Articles. 630. https://scholarworks.wm.edu/vimsarticles/630 This Article is brought to you for free and open access by W&M ScholarWorks. It has been accepted for inclusion in VIMS Articles by an authorized administrator of W&M ScholarWorks. For more information, please contact [email protected]. LARVAL DEVELOPMENT OF CITHARICHTHYS CORNUTUS, C. GYMNORHINUS, C. SPILOPTERUS, AND ETROPUS CROSSOTUS (BOTHIDAE), WITH NOTES ON 1 LARVAL OCCURRENCE , 2 3 JOHN W. TUCKER, JR. ABSTRACT Developmental series of 4 of the 12 species of Citharichthys and Etropus known from the western North Atlantic and Gulf of Mexico are illustrated and described. The series consist of C. cornutus (prefiexion to nearly transformed, 2.2-17.4 mm body length, BL), C. gymnorhinus (preflexion to late transformation. 4.4-12.9 mm BL). C. spitoptcrus (prefiexion to juvenile, 3.7-25.4 mm BL), and E. crossotus (prefiexion to nearly transformed, 4.6-10.8 mm IlL). Data from this study and that for 2 species previously rlcscribed permit identification oflarvaeof 6 of the 12 species. For the species investigated, caudal fin formula (4-5-4-4) is the most rei iable indi­ cator for the group of genera Citharichthlls, Cyclopsctta, Etropus, and SllaCi1Un. Numberofelongate dorsal rays, degree of cephalic spination, and pigmentation are most usefuHor determining genus for known forms. Number of elongate dorsal rays, number of caudal vertebrae. pigmentation, mor­ phology, and number of gill rakers are most useful for identification of Citharichthys and Etropus larvae that have been described. Citharichthlls cornutus larvae have no pectoral melanophore. little notochordal pigmentation, heavy lateral pigmentation, 3 elongate dorsal rays, and develop 6 left pelvic rays and 25-26 caudal vertebrae. Flexion is complete at 9-10 mm SL and transformation at about 18 mm S1. Larvae have been collected during all seasons. Caudal fin development in C. cornu/us is typical of the four species described here. Citharichthlls gymnorhinus larvae have no pectoral melanophore, little notochordal pigmentation, light lateral pigmentation except for a caudal band. 3 elongate dorsal rays. and de­ velop only 5 left pelvic rays and 23-24 caudal vertebrae. Flexion is complete at 7-8 mm SL and trans­ formation probably at about 18 mm SL. Larvae have been collected duringall seasons. Citharichthlls spi/opterus larvae have no pectoral melanophore. little notochordal pigmentation, light lateral pig­ mentation, a blunt snout, a deep body, 2 elongate dorsal rays, and develop 6 left pelvic rays and 23-24 (rarely 25) caudal vertebrae. Flexion is complete at 7-8 mm SL and transformation at 9-11 mm SL. Larvae have been collected from September through April. Etropus Ct'OSsotUB larvae have a melano­ phore at the base of the peetoral fin, heavy notochordal pigmentation, heavy lateral pigmentation, 2 elongate dorsal rays. and develop 6 left pelvic rays and 25-26 (very rarely 24) caudal vertebrae. Flexion is complete at 9-10 mm SL and transformation at 10-12 mm S1. Larvae have been collected in May and August and probably occur from March to August. Twelve species of the flatfish genera Citharich­ al. 1975; Dowd 1978) and adults (Dawson 1969; thys and Etropus (subfamily Paralichthyinae, Topp and Hoff 1972; Christmas and Waller 1973) family Bothidae) are recognized from the west­ indicates that some species may represent sig­ ern North Atlantic (Table 1). Because of their nificant components of estuarine and marine small size at maturity, these fishes are presently food webs. used only by the petfood and fish meal industries Larvae in the Citharichthys-Etropus complex (Topp and Hoff 1972). However, the abundance are difficult to distinguish and are often ignored of larvae (Richardson and Joseph 1973; Smith et or classified as "unidentified bothids" in species composition analyses (e.g., Fahay 1975). Of the 12 western North Atlantic species, only C. arcti­ 'Contribution No. 1037, Virginia Institute of Marine Sci­ frons and E. microstomus have been described in ence, Gloucester Point, VA 23062. detail (Richardson and Joseph 1973). Citharich­ 2Derived from a thesis submitted to North Carolina State University in partial fulfillment of the requirements for the thys comutus, C. flymnorhinus, C. macrops, and Master of Science degree. E. rimosus have been briefly described by Dowd 'School of Marine Science of the College of William and (1978). Larvae of the remaining species have not Mary, Virginia Institute of Marine Science, Gloucester Point, VA 23062. been reported previously. Hsiao (1940) mis- Manuscript accepted October 1981. 35 FISHERY BULLETIN: VOL. 80. NO. 1. 1982. FISHERY BULLETIN: VOL. 80. NO.1 takenly described Bothus sp. larvae as E. cros­ sonal collections in the Cape Fear River estuary, sotus. one from a CP&L collection in the ocean just off In this paper I presentdescriptions of larvae of Cape Fear, and three from Texas A&M collec­ C. comutus, C. gymnorhinus, C. spilopterus, and tions in the Gulf of Mexico off Texas were used E. crossotus and summarize data useful for iden­ for morphometries, counts, and general develop­ tifying Citharichthys and Etropus larvae. ment. Other specimens from Texas A&M, NMFS (Beaufort, Galveston, and Panama City), MATERIALS AND METHODS and RSMAS collections were used for compari­ son and additional count data. Thirty E. cros­ Abbreviations sotus specimens from LSU collections from the Gulf of Mexico off Louisiana and one from a The following institutional abbreviations are NCSU collection were used for morphometries, used: CP&L = Carolina Power and Light Com­ counts, and general development. Other speci­ pany, Raleigh, N.C.; GCRL = Gulf Coast Re­ mens from Texas A&M collections were used for search Laboratory, Ocean Springs, Miss.; GMBL comparison. = Grice Marine Biological Laboratory, College of Comparative larval material of other species Charleston, S.C.; LSU = Louisiana State Univer­ was also examined. Citharichthys sp. A (prob­ sity, Baton Rouge; NCSU = North Carolina State ably C. abbotti) specimens came from Texas University, Raleigh; NMFS = National Marine A&M; Citharichthys arctifrons specimens from Fisheries Service, NOAA (four laboratories­ NMFS (Beaufort), SCMRRI, and VIMS; a Cith­ Beaufort, Galveston, Panama City, and LaJolla); arichthys sp. B (probably C. dinoceros) specimen OSU = Oregon State University, Corvallis; from RSMAS; and Citharichthys (macrops?) RSMAS = Rosenstiel School of Marine and specimens from GCRL, RSMAS, and VIMS. Atmospheric Science, University of Miami, Fla.; Larvae of the eastern Pacific species Citharich­ SCMRRI = South Carolina Marine Resources thys sordidus, C. stigmaeus, and C. xanthostigma Research Institute, Charleston; Texas A&M = came from NMFS (La Jolla). Other specimens of Texas A&M University, College Station; UNC = Pacific Citharichthys spp. came from OSU; University of North Carolina, Institute of Ma­ Etropus microstomus specimens from NMFS rine Sciences, Morehead City; USNM = U.S. (Beaufort) and VIMS; Etropus sp. A (probably National Museum of Natural History, Smith­ E. rimosus) specimens from CP&L, NMFS sonian Institution, Washington, D.C.; VIMS = (Panama City), and RSMAS; Cyclopsetta fim­ Virginia Institute of Marine Science, Gloucester briata specimens from NMFS (Beaufort), Point. RSMAS, SCMRRI, and Texas A&M; and Syaci­ um papillosum specimens from RSMAS and Specimens Texas A&M. Juvenile and adult specimens were examined Larval and juvenile specimens used in this to determine permanent characters. Specimens study were obtained from several sources. Forty­ of C. arctifrons, C. macrops, C. spilopterus, E. seven C. cornutus specimens from SCMRRI crossotus, E. intermedius (cf. E. crossotus), E. (MARMAP ichthyoplankton survey) collections microstomus, and E. rimosus came from USNM; in the South Atlantic Bight and five specimens Citharichthys cornutus and C. gymnorhinus from RSMAS collections from the Gulfof Mexico specimens from GMBL; Citharichthys macrops off western Florida were used for morpho­ specimens from UNC and a personal collection; metries, counts, and general development. Seven and Citharichthys spilopterus and E. crossotus additional RSMAS specimens were used for specimens from NCSU. counts. Other specimens from NMFS (Beaufort) Description of caudal skeleton development collections in Onslow Bay, off North Carolina, was based on study of the entire developmental were used for comparison. Twenty-eight C. gym­ series of C. comutus and comparison with the norhinus specimens from SCMRRI collections series of the three other species described. and 12 from RSMAS collections were used for Calcified components of the caudal skeletons of morphometries, counts, and general develop­ nearly all the specimens could be seen following ment. Other specimens from NMFS (Beaufort) light staining with Alizarin Red Sin 1% aqueous collections were used for comparison. Fifty-five potassium hydroxide solution. Twenty cleared C. spilopterus specimens