External morphology of newly-hatched juveniles of Aegla lata (Crustacea, Aeglidae)

ABSTRACT

Aegla is a genus of freshwater anomuran Crustacea known for having epimorphic postembryonic development. The newly-hatched juveniles’ morphology have been described for only 11 of the 93 known species. These descriptions are important tools for identifying juveniles and useful characteristics for phylogenetic analyses. This study aims to describe and illustrate the external morphology of the first juvenile stage of Aegla lata. Ovigerous females were collected, fed, and monitored periodically in the laboratory until the eggs hatched. The newly-hatched juveniles were fixed in an alcohol series and preserved in a 70% alcohol and glycerine solution (2:1 ratio) for subsequent dissection and analysis under light microscopy. The appendages were illustrated using a camera lucida and then described. Scanning electron microscopy was used to analyse some specimens, allowing the detailed observation of the setal morphology, some cephalothoracic appendages, and lineae aeglicae. Pappose setae were also observed in the protopod and dactylus of cheliped. The newly-hatched juvenile of A. lata has a set of the following characteristics: basal segment of antennule with serrate setae; distal segment of antennule with pappose setae; merus of second maxilliped with simple setae; and merus of third maxilliped without simple setae.

KEYWORDS:

• Anomura
• description
• postembryonic development

Acknowledgments

We thank the Laboratory of Electron Microscopy and Microanalysis of UEL for assistance in obtaining the images of specimens examined in this study. LSAS thanks the National Council for Scientific and Technological Development (CNPq) for the scholarship provided (grant nº 132273/2015-2). GMT thanks CNPq for the productivity grant provided (nº 303802/2022-7). The authors also thank the Academic Writing Center of the State University of Londrina for assistance with English language developmental editing.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The work was supported by National Council for Scientific and Technological Development (CNPq).