ABSTRACT
Complete larval morphological descriptions are currently only known for three of the 48 species of genus Lysmata. The present study describes and illustrates the larval development of Lysmata amboinensis (De Man) reared under laboratory conditions. Lysmata amboinensis larval development is composed by a total of ten zoea and a decapodite stage. The first zoeal stage larvae presents sessile eyes, a carapace with a pterigostomial spine and anterio-ventral marginal denticles, a long, slender, and pointed rostrum, an antennal exopod terminally articled, a pleon with five somites, the fifth one bearing a pair of dorso-lateral spines on the posterior margin, and a triangular shaped telson with 7+7 posterior processes. The decapodite resembles a smaller adult and has extremely long antennas (more than twice the total length of the decapodite), the first two pair of pereiopods with chela, first four pairs of pereiopods with reduced and entire exopods, and fully developed pleopods. The morphological features of L. amboinensis are compared with those currently available for the larval stage of the genus Lysmata.
Subject(s)
Cypriniformes , Decapoda , Animals , Decapoda/anatomy & histology , Eye , Humans , Laboratories , Larva/anatomy & histologyABSTRACT
The present work describes and illustrates in detail the six zoeal stages of Albunea paretii collected from plankton samples on the Amazon continental shelf in Brazil. The morphological characters are compared with those of other known albuneid larvae. As in other albuneids, the zoeae of Albunea paretii have a semi-globose carapace, a long rostral spine and a pair of long posterolateral spines on pereon, as well as three aesthetascs on the antennule of zoea I, a strong antennal spinous process and a convex telson with a stout posterolateral spine. The zoeal morphology of Albunea paretii and other species of the genus differs, especially regarding the unique presence of the posterolateral spine only on the 5th pleonite in zoea I-IV and the absence in later zoeal stages. The differing features of the albuneid subfamilies are in the telson, antenna and maxilla format and number of setae.
Subject(s)
Anomura , Decapoda , Animals , Brazil , Larva , PlanktonABSTRACT
Of the 12 species of Thor described until present date, only three (25%) have their complete larval development known. Present work describes the complete larval development of Thor amboinensis, based on laboratory-reared material. The spent females were identified through the analysis of the partial sequences of the mitochondrial DNA barcode, also used for the reconstruction of the phylogenetic relationships within the recently resurrected and recognized family Thoridae Kingsley, 1879. Eight zoeal stages and one decapodid complete this species larval development. In the genus Thor, the number of zoeal stages varies greatly from two (T. dobkini) to eight (T. amboinensis and T. floridanus). The larvae of T. ambionensis and T. floridanus are readily distinguished from each other by the ornamentation of the ventral margin of the carapace and the pereiopods development. The first zoeal stage of T. amboinensis described by Yang & Okuno (2004) and the one described in present study are very similar. A brief discussion on the morphological characters and on the number of zoeal stages of the genus, as well as of the previous larval descriptions is made. The phylogenetic analysis suggest cryptic speciation for geographical separated populations of T. amboinensis, paraphyly of the genus Eualus, and the reassignment of E. cranchii to a different genus.
