Allometry of freshwater crab, hypolobocera aequatorialis (Pseudothelphidae), native to Ecuador.

Abstract

Freshwater crab Hypolobocera aequatorialis is native to Ecuador, the objective of this work was determining its allometry. Field samplings were done between May and June 2022, in the Pintohuayco site, Province of Chimborazo, Ecuador. The recorded morphometric variables were width, length, and height of the carapace (CW, CL, CH, respectively), and chelae (ChW, ChL, ChH, respectively), as well as the individual weight. Abdomen width (AW) was registered only in females. The models: linear, thresholds and two segments were fitted to natural logarithm-transformed data. The best model was selected using the bias corrected weights of the Akaike Information Criterion (Wi AICc). Size-weight relationship was estimating by a power model. A total of 201 individuals were collected. Females presented larger sizes than males. The best-fit models were two-segment and threshold. The allometry was principally isometric (b = 1) and negative allometric (b < 1) for the first and second segments, respectively. The sizeweight relationship showed a negative allometry (b < 3). We assume the inflection points of the best models show morphometric changes related to use of habit as feeding, protection against predators, and mating behavior.