Embryonic development of the estuarine crab Neosarmatium indicum (Crustacea: Brachyura: Sesarmidae) from the mangroves of the Okinawa Island, Japan

Abstract

:The complete embryonic development of the mangrove sesarmid crab Neosarmatium indicum (A. Milne Edwards, 1868) was described based on internal and external morphological changes in live fertilized eggs reared in the laboratory. Several pairs of N. indicum were collected from the Nuha River mangrove swamp of the southern Okinawa Island, Japan, which is consisted mainly with the mangrove Kandelia candel, and densely populated by the genus Perisesarma and Neosarmatium indicum . The fertilized eggs were macrolecithal, centrolecithal and spherical in shape, filled with uniform dark olive colour, without evidence of any development. The diameter of fertilized egg was 0.36 mm, which increased to 0.47 mm before hatching. Embryo development from fertilized eggs to hatching (first zoea stage) lasted average of 16 days at 25 0 C and salinity at 80‰. Sixteen stages of embryonic development were categorized by following continuous observation using an optical DIC microscope equipped with digital camera, video camera and printer. After 24 hours of incubation, fertilized eggs became 32-celled stage of development. Before hatching, many chromatophores (mostly black) were evident in the abdominal segments and the telson of embryos. At the end of 16 days incubation, the zoea larvae were successfully hatched out, which were reared in the laboratory conditions for further development.

Morphology of the complete embryonic and larval development of commercially important mud crabScylla paramamosain

“…In brachyuran crabs, females incubate their embryos under the abdomen from spawning to hatching (Garcia‐Guerrero & Hendrickx, 2004; Sarker et al, 2012), and S. paramamosain exhibited similar features (Figure 1A–a). In S. paramamosain , female crabs contained 16 pleopods (Figure 1A‐b,c) with two different microstructures, plumose setae (Figure 1B) and hair‐like setae (Figure 1C).…”

“…The description of embryonic development was based on 100 embryos ( n = 100) from five ovigerous female crabs (20 embryos from each). The terminology used for embryonic development description was guided by previous studies (Ates et al, 2012; Garcia‐Guerrero & Hendrickx, 2004; Ikhwanuddin et al, 2015; Sarker et al, 2012).…”

“…Many scientists attempt to distinguish embryonic stages based on morphological features (Garcia-Guerrero & Hendrickx, 2004;Sarker et al, 2012), morphometric measurements (Stevens, 2006), In studies conducted before 2007, the dominant species of mud crab along the coast of China was described as Scylla serrata, however, subsequent work based on morphology and genetics showed that it was actually Scylla paramamosian (Lin, 2008;Lin et al, 2007).…”

Embryonic development of marine ornamental shrimp, Lysmata amboinensis (De Man, 1888)

“…In several studies the eggs stage of crustacean have been divided on the presence of distinct morphological features such as eye, heartbeat and main appendages formation (Muller et al, 2003;Sarker et al, 2012;Tracey et al, 2013;Romero-Carvajal et al, 2018;Liu et al, 2020). However, such morphological characters only start to appear in the middle of embryonic development (Dinakaran et al, 2013).…”

“…Biological information such as reproduction, embryonic development, and larval development are essential for the development of marine ornamental aquaculture breeding technology. In decapod crustaceans, embryonic development is associated with changes in embryo color, size and morphology during reproductive cycle (Sarker et al, 2012;Romero-Carvajal et al, 2018). Crustacean embryonic development offers an exclusive, valuable, and perceptive instrument for both developmental processes and physiological regulatory mechanisms (Dinakaran et al, 2013).…”