Description 

A grey shrimp with bright pink legs and chelae. The carapace and abdomen are pale grey marked with darker grey lines in much the same way as the differently coloured Yellow Pyjama Shrimp but this shrimp lives in a different habitat and has different associations. 

Carapace: The carapace is pale grey with dark grey double lines that become continuous with similar lines on the body. these lines often have a pink colour. The side of the carapace may be distinctly striped but more often it is unmarked. 

The abdomen is pale grey with four double lines along each side. These are grey or pink. There is a white band on segment 1. 

The legs are bright pink with pale joints

The rostrum is pink. The antennae are pink-grey. 

The pincers are pink with faint pale marbling. 

Variant form (“Grey Pyjama Shrimp”)

There is another Pyjama Shrimp that is similarly marked but entirely in shades of grey. This may be a separate species but we do not have enough evidence of separate ecology and associations to say so. We have not seen a pair made up of grey and pink individuals (see photo above). 

The carapace is pale grey with well-defined dark grey double lines on its upper half. 

The abdomen is pale grey with four pairs of dark grey double lines that are continuous with those on the carapace. 

Legs, pincers and antennae are grey, the last with slight marbling. 

Identifying Features

Similar Shrimps

Red Pyjama Shrimp, Yellow Pyjama Shrimp. Brown Pyjama Shrimp.

Nomenclature

This is one of the shrimps commonly grouped under the species name Alpheus ochrostriatus (an invalid name). The group can be split into four, possibly more, by colour, habitat and associations. These are the Yellow Pyjama Shrimp, the Pink Pyjama Shrimp, the Brown Pyjama Shrimp and the Red Pyjama Shrimp. 

Ryanskiy (2016) p9. has images of a similar-looking shrimp and gives the name Alpheus sp. common name Pink-Clawed Snapping Shrimp. Length up to 3. 2 cm. Distribution South and Western Pacific – Papua New Guinea. 

Humann & DeLoach (2010) p85 has images of a similar-looking shrimp and gives the name Alpheus species 2, common name Undescribed. Size to 3 cm. Papua New Guinea. One of three species with similar markings. 

There is an all-grey version of this shrimp which should possibly be split off as a separate species. We have not done so because it tends to have a pink tinge to the chelae and legs in some cases and seems to occupy a similar ecological niche. However, we have yet to see a pair comprised of an unequivocal pink and an equally definite grey form. More observation of its behaviour and associations will clarify the relationship.