New Species of Estuarine Crab

• 09 Nov 2022

Why in News?

Recently, researchers have discovered a new species of Estuarine Crab at the Mangroves of Parangipettai near the Vellar River estuary (an area where river meets the ocean) in Cuddalore district, Tamil Nadu.

• The species has been named ‘Pseudohelice Annamalai’ in recognition of Annamalai University’s 100 years of service in education and research.

What are the Key Facts about Pseudohelice Annamalai?

• About:
  • This is the first ever record of this genus, Pseudohelice, collected from high intertidal areas in front of the Centre of Advanced Study (CAS).
    • Till date, only two species, namely “Pseudohelice Subquadrata” and “Pseudohelice Latreilli” have been confirmed within this genus.
• Geography:
  • The species discovered is distributed around the Indian subcontinent and the eastern Indian Ocean.
• Features:
  • Pseudohelice annamalai is distinguished by dark purple to dark grey colouring, 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.
  • This species is not aggressive and can move fast like other intertidal crabs.
• Habitat:
  • The species inhabits muddy banks of mangroves, and the burrows were located near the pneumatophores of Avicennia mangroves.
  • Burrows have a depth of 25-30 cm and are branched, with larger pellets around the entrance.
• Significance:
  • 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

Source: TH