2008 SOUTHEASTERN NATURALIST 7(3):565–567 Color Photographs for Morphological and Developmental Differences in Three Species of the Snapping Shrimp Genus Alpheus (Crustacea, Decapoda) Heather R. Spence1 and Robert E. Knowlton2,* Abstract - Living, freshly collected individuals of three species of snapping shrimps were studied to determine any differing morphological, developmental, and ecological features: Alpheus heterochaelis, collected from Beaufort, NC; A. angulosus, found mainly in Jacksonville, FL, but also at one site in Beaufort; and A. estuariensis, collected at another Jacksonville site. Structural characteristics of these superficially similar species are summarized, with particular attention to coloration. Adult A. angulosus individuals have blue-green 2nd antennal fl agella (vs. tan in the other two species) that are significantly shorter than those of A. heterochaelis. Alpheus angulosus and A. estuariensis bear smaller eggs (<1 mm, regardless of embryonic stage) than A. heterochaelis (>1 mm), and the former species displays the zoea larval form typical of alpheids (vs. abbreviated larval development in A. heterochaelis). Note: The text for this article appears in the Southeastern Naturalist volume 7, issue 2, 2008, pp. 207–218, but was erroneously printed with grayscale figures. The accompanying figures are herein reprinted in full color as originally intended. 1Department of Biology, University of Massachusetts, North Dartmouth, MA 02747-2300. 2Department of Biological Sciences, George Washington University, Washington, DC 20052. *Corresponding author - knowlton@gwu.edu. Figure 1. Dorsal view of male A. heterochaelis, showing “balaeniceps- type” minor chela. 566 Southeastern Naturalist Vol.7, No.3 Figure 2. a. Tan to pale blue tail fan of A. estuariensis (also characteristic of A. angulosus). b. Tail fan of A. heterochaelis, with characteristic bright blue spots on uropods. Figure 3. a. Rostrum of A. angulosus, exhibiting triangular base (indicated by arrow) and fl anked by eyes. b. Rostrum of A. estuariensis, which lacks triangular base (as does the rostrum of A. heterochaelis). Figure 4. a. Anterior region of A. angulosus exhibiting relatively wide minor chela and paler coloration after being kept in the laboratory. b. Anterior region of female A. heterochaelis, showing thinner (vs. A. angulosus) minor chela and tan antennal fl agella. c. Anterior region of A. estuariensis, exhibiting characteristic slender minor chela, tan antennae, and angular dactylus of major chela. a b A. estuariensis A. heterochaelis a b A. angulosus A.estuariensis a b c A. angulosus A. heterochaelis A. estuariensis 2008 H.R. Spence and R.E. Knowlton 567 Figure 5. Dorsal view of A. estuariensis abdominal segments, showing characteristic banding pattern. Figure 6. Dorsolateral view of A. angulosus head, showing blue antennal fl agella (one indicated by arrow). Figure 7. Eggs of A. angulosus (top) and A. heterochaelis (bottom) about halfway through embryonic development. Egg size: top, 0.71 x 0.60 mm; bottom, 1.12 x 1.03 mm. Figure 8. Stage II zoea larva of A. angulosus. Total length = 2.56 mm.