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This paper was submitted by the faculty of FAU’s Harbor Branch Oceanographic Institute.

Notice: ©1977 Marine Environmental Sciences Consortium of Alabama. The final version of this manuscript is published by http://goms.disl.org/ and may be cited as: Gore, R. H. (1977). Studies on decapod crustacea from the Indian River region of Florida. VII. A field character for rapid identification of the swimming crabs Callinectes ornatus Ordway, 1863 and C. similis Williams, 1966 (Brachyura: Portunidae). Northeast Gulf Science, 1(2), 119-123.

Notes 119

STUDIES ON DECAPOD CRUSTA­ C. ornatus and C. similis. Specimens used CEA FROM THE INDIAN RIVER in this study are deposited in the REGION OF FLORIDA. VII. A FIELD Reference Collection of the Indian River CHARACTER FOR RAPID IDENTI­ Coastal Zone Study, Link Port, Ft. FICATION OF THE SWIMMING Pierce, Florida. CRABS Callinectes ornatus ORDWAY, COLOR PATTERNS 1863 AND C. similis WILLIAMS, 1966 (BRACHYURA: PORTUNIDAE) ­ Callinectes ornatus - Many of the The portunid crabs Callinectes ornatus Indian River specimens varied from the and C. similis are two very closely general color pattern described by related species; C. similis was con­ Williams (1974) being either lighter or fused with C. ornatus for a number of darker greenish brown, although years until separated by Williams (1966). similarities were evident primarily in Both species are common on seagrass overall hue of the dorsal carapace, and in beds in the Indian River lagoon along the cheliped color, as well as in hue and central eastern Florida coast. Ecological pattern on the walking legs. This species studies in this area have shown that is uniformly olive brown or green, with juveniles of both species are also distinct ivory white tips on all the seasonally abundant on lagoonal anterolateral carapace spines. The overall seagrass beds. Adult male crabs are easily impression usually is that of an olive separated to species on gonopod brown crab (Plate I A). Ventrally, the morphology, whereas females are less meri of the walking legs and the sternal easily distinguished on gonopore con­ regions are ivory white and the distal figuration (Williams, 1974). However, segments of the pereiopods are varying because of great similarity in shades of greenish-brown (Plate I C). morphological features juveniles of the Viewed frontally, the chelipeds are ivory two species have been relatively difficult white, flushed dorsally with olive green; to identify as to species. Field data the finger tips are brown or tan (Plate I obtained from large numbers of live D). Most noticeable, however, are the juvenile specimens, and smaller numbers dactyls of the fifth pereiopods which are a of adults, in both species show that a uniform golden brown or light tan, and distinct difference in color patterns the propodus which appears distinctly between the two species occurs, especially banded with translucent yellow in cheliped color, and color and pattern proximally, and a dark bluish-green of the propodus and dactylus of the distally (Plate 1 A, B). modified fifth pereiopod (swimming leg). These color patterns are sufficiently Callinectes simi/is - The overall color of distinctive to form a valuable field this species has been described accurately character allowing easy identification of by Williams (1974) and the Indian River live juvenile and adult specimens of C. specimens agreed in most respects. The ornatus and C. similis. They may also be dull orange or orange-red spot on either used to separate recently preserved (up to side of the carapace posteriorly was not six months in some cases) material of always present, or if present was not these two species. I provide color notes always distinct. Viewed dorsally, the and photographs of these patterns to overall impression one gets is that of an enable other investigators working with olive drab crab, more greenish than C. live or recently collected and preserved ornatus, and often irregularly speckled material to quickly distinguish between with light gray (Plate 1 E). The iridescent 120 Northeast Gulf Science Vol. 1, No.2. December 1977 Plate 1 A-D . - Callinectes ornat us Ordway , 1863 . Male, 58 m m cw , Indian River, St. Lucie Co., Ft. Pierce, Florida. SIF P 89 :2920. A, z ~ Dorsal view; E, Right pereiop od 5, dorsal view ; C, Ventral view; D , Fr ontal view. ~ Plate 1 E·H. - Callinectes simi/is William s, 1966. Mal e, 59 mm cw , Ind ian River , St. Lu cie Co ,, Ft. Pier ce, Flo rida. S IF P 89:2921. E, Do rsal ... view; F, Left p erei opod 5 , dorsal view ; G, Ve ntra l view; II , Frontal view . ...N 122 Northeast Gulf Science Vol. 1, No.2. December 1977

patches described by Williams (1966, translucent blue, at times almost 1974) are also usually quite distinct. completely clear, the species is C. similis. Ventrally, the sternal region is ivory white Small juveniles (5-25 mm cw) of both C. as in the above species. The proximal similis and C ornatus, when viewed portion of the meri of the walking legs is frontally, have the interior surfaces of the also white, but the latter become diffused chelipeds olive drab to tan, but those of with blue distally, this color becoming C. similis appear slightly diffused with more intense on the outer segments of the blue. I have found these differences to be walking legs. The dactyls of the latter consistent in ecological collections from range from deep red to burnt orange, as in the Indian River area and the juveniles of C. ornatus, but are also diffused with the two species may thus be easily sorted blue, which usually is not seen in C. in the field saving much time spent in ornatus (Plate I G). The common name identification in the laboratory. of Lesser Blue Crab seems appropriate The only other species which occurs for this species when viewed frontally commonly in the Indian River area and (Plate I H) and the interior surfaces of the coastal regions to the north is the chelipeds range from light to cerulean or commercial blue crab, Callinectes china blue, becoming darker on the distal sapidus Rathbun, 1896. Juveniles and portions and blending into olive drab ad ults of this species are not nearly as dorsally. The color may even be purple on abundant as the previous two species, a the underside of the meral ridge, carpal possible result of an intensive local joint, and the tips of the fixed and commercial fishery for blue crabs. Adults movable fingers in some specimens. of C. sapidus, as the common name Younger specimens are a solid, reflects, are usually of a distinct bluish uninterrupted blue in this region with the hue overall, and both adults and larger anterior and distal part of the palm juveniles (30 mm cw and wider) may be appearing as if dipped in blue ink; the quickly separated from the preceding two fingers tend to be more whitish. The most species by the absence or rudimentary noticeable differences between this development of the submesial frontal species and C. ornatus are seen in the teeth. Juveniles of C. sapidus have no propodi of pereiopod 5 which are distinct banding on the propodi or dactyli translucent olive drab proximally and of the swimmerets, and in in adults these distally, banded with translucent blue appendages are usually a distinct deep medially; the joints are speckled with blue or blue-gray in color. fuchsia, and the entire outer and inner surface of the dactyl is pale translucent blue (Plate I E, F). ACKNOWLEDGEMENTS Juveniles - Juvenile specimens (at least I thank Mrs. Linda J. (Becker) 25 mm carapace width cw, and larger) of Girardin for drawing my attention to the both species may most easily be separated characters discussed above, and for by the color of the propodus and dactyl of patiently sorting much of the ecological the swimmeret (pereiopod 5). If the material on which this paper is based. propodus is regularly and distinctly This is Scientific Contribution No. 87 banded and the dactyl is a uniform tan or from the Smithsonian Institution­ yellow color, the species is C. ornatus. If Harbor Branch Foundation, Inc., the propodus is faintly and more Scientific Consortium, Link Port, Ft. irregularly banded and the dactyl is Pierce, Florida 33450. LITERATURE CITED Williams, A. B. 1966. The western Atlan­ tic swimming crabs Callinectes ornatus, C. danae, and a new, related species (Decapoda, Portunidae) Tulane Stud. Zoo!., 13:83-93, figs. 1-5. ______. 1974. The swimming crabs of the genus Callinectes (Deca­ poda: Portunidae). Fishery Bull. U. S. Fish Wildl. Serv., 72 (3): 685-798, figs. 1-27. Robert H. Gore, Smithsonian Institu­ tion, Ft. Pierce Bureau, Ft. Pierce. FL33450.