New species of estuarine crab was discovered in Cuddalore, Tamil Nadu

Context

Researchers of Annamalai University have discovered a new species of estuarine crab in the mangroves of Parangipettai near the Vellar River estuary in the Cuddalore district.

What is an Estuary?

An estuary is an area where a freshwater river or stream meets the ocean. In estuaries, the salty ocean mixes with a freshwater river, resulting in brackish water.

About

About the Species:

The species has been named Pseudohelice Annamalai in recognition of Annamalai University’s 100 years of service in education and research.
This is the first-ever record of this genus, Pseudohelice, collected from high intertidal areas in front of the CAS.
So far, only two species — Pseudohelice subquadrate and Pseudohelice Latreille.

Features:
- Pseudohelice Annamalai is distinguished by dark purple to dark grey coloring, with irregular light brown, yellowish brown, or white patches on the posterior carapace with light brown chelipeds.
- The new species is small and has a maximum width of up to 20 mm.
- The species inhabits muddy banks of mangroves, and the burrows were located near the pneumatophores of Avicennia
- Burrows have a depth of 25-30 cm and are branched, with larger pellets around the entrance.
- This species is not aggressive and can move fast like other intertidal crabs.
- As many as 17 species of intertidal crabs have been recorded in the same region.

Significance of the Species:

The occurrence of Pseudohelice in India links the distribution gap between the western Indian Ocean and the western Pacific Ocean.
The new species provides additional evidence of the geographic isolation of the eastern Indian Ocean for some marine organisms.

Location: The Vellar River Estuary