Abnormal record of coastal horseshoe crab (Tachypleus gigas Müller, 1785) in Subang, West Java, Indonesia

Abstract

The xiphosurids are a typical chelicerae group with massive morphological, anatomical, biochemical, and ecological documentation. Despite this study, information about extant horseshoe crab abnormalities is underexplored, especially in the Indonesian region. Thus, this study aims to investigate the abnormal horseshoe crab in Subang, West Java. This research was conducted from January until February 2020 in Legon Wetan, Subang, West Java. Here, we only documented abnormalities of extant xiphosurids namely Tachypleus gigas. During the study, we greatly found extant abnormal xiphosurids by identifying 45 specimens with a wide range of abnormalities on the cephalothorax (prosoma), thoracetron (opisthosoma), telson, and appendages. The abnormal coastal horseshoe crab found also included adults (male and female) and juveniles ranging from 11.6 cm to 21 cm of carapace width. We note that the most common abnormal body parts are the cephalothorax and the thoracetron. Although the original cause may be unknown, the three main causes of the abnormality-inducing which are injuries such as self-injuries or fishing net injuries, physiologic developmental abnormalities or teratologies, and pathologies.