Yellow Pyjama Snapping Shrimp, Alpheus ochrostriatus

Yellow Pyjama Snapping Shrimp

Alpheus ochrostriatus complex

Yellow Pyjama Snapping Shrimp

Alpheus ochrostriatus complex

undescribed

Description

A very common shrimp found on coral reefs.

Carapace: The carapace is pale grey with ten pairs of red-brown longitudinal stripes that are continued onto the abdomen.

The abdomen has the same pattern in the same colours. It is intersected by conspicuous white bands on segments 1, 4 and 5.

The rostrum is yellow and the antennae are yellow or grey.

The pincers are pale, decorated with two lines of conjoined red circles like those on the carapace and abdomen. The legs are bright yellow, contrasting with the body.

The tail is yellow.

Identifying Features

Similar Shrimps

This is one of the shrimps commonly grouped under the species name Alpheus ochrostriatus (itself 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.

We have applied names to the colour variations of Pyjama Shrimps. They differ consistently in colour, habitat and associations. Pair formation only involves individuals of the same colour form, in our experience.

The Yellow Pyjama Shrimp has bright yellow-green legs, tail and rostrum and the carapace and abdomen are ochre with light brown stripes.

The Brown pyjama shrimp has similar yellow green legs, tail and rostrum and the carapace and abdomen are grey with brown stripes. The main distinguishing feature is the dark grey pincers. In the yellow pyjama shrimp the pincers have longitudinal red lines lines similar to the carapace and abdomen.

The Pink Pyjama Shrimp has a grey abdomen with pink stripes and pink extremities. Included in this designation are all-grey forms although we have yet to see them pair up with the classic pink.

The Red Pyjama shrimp has a distinctively different dark red carapace. and has different geographical distribution, habitat and associations.

Nomenclature

The scientific name Alpheus ochrostriatus, Karplus, Szlep and Tsurnamal, 1981 has been applied to this shrimp but is considered invalid, having not been formally described (hence a nomen nudum = naked name) ( Debelius 2001).

Anker (2010) considers that there are 2 to 3 sibling species within the name Alpheus ochrostriatus.

Several non-technical books illustrate the Yellow Pyjama Shrimp giving it the scientific name Alpheus ochrostriatus in the text.

Ryanskiy (2016) p9. has images of a similar-looking shrimp and gives the name Alpheus sp common name Yellow Snapping Shrimp. Length up to 6 cm. Distribution Indo-Pacific – Red Sea, Maldives, Seychelles, Thailand, Oman, Vietnam, Japan, Philippines, Indonesia, Australia.

Hayashi & Shiratori (2003) Alpheus djeddensis from Japan.

Alternate common names Yellow Snapping Shrimp, White-saddle Snapping Shrimp, Ryanskiy (2016), Fine Striped Snapping Shrimp (Debelius) 2001)

We have not seen pair formation between Pyjama shrimps of more than one of the colour varieties described in this book A grey form may eventually be separated from the Pink. We have not seen pair formation between the two but their behaviour is very similar and more observations will be needed.

Ecology

HABITAT Coarse sand, pebbles, coral and shell debris on the fringing reef edge is the preferred substrate. but fine sand at the base of walls, and the essentially sand-free shell debris found in spur and groove outer reef are also used.

Depth range 5 to 30 metres

Proximity to reef One feature is constant: they always construct their burrows close to the reef.

NATURAL HISTORY

This is a very adaptable shrimp capable of working a wide range of substrates from fine sand to pure coarse shell grit to coarse sand with large coral rock and shell fragments. This probably accounts for how commonly it is seen as well as the fact that, like Scuba Divers, its preferred habitat is a healthy coral reef.

It is very much a constructor rather than a bulldozer. In substrate with many coarse coral fragments, these shrimps construct beautifully finished burrow entrances. A semicircle of meticulously arranged coral pieces stabilises one side of the entrance. In the opposite direction, a soft sand runway is created not primarily by bulldozing but by picking out any coral pieces and carrying them back to add to the wall. Sometimes the whole edifice is based on a sand cone elevated above the surroundings.

It prefers sheltered conditions and where there is a strong current. It is only found in the lee of boulders and bommies.

It is not a species specialist and associates with several shrimpgobies, all of which share the preference for coral reef environments.

The association, in most cases at least, starts at a very early stage in the adult life cycle and we have seen some truly tiny pairs.

Feeds on organic sediment, algae, and small invertebrates, Ryanskiy (2016).

Distribution

Published distribution:

(of the so-called ‘Alpheus ochrostriatus’ group). Red Sea, Maldives, Philippines, Papua New Guinea Debelius (2001) Indo-Pacific: Red Sea, Oman, Seychelles, Maldives, Thailand, Vietnam, Japan, Philippines, Indonesia, Australia, Ryanskiy (2016). Flores and Bali, Indonesia. Widespread Indo-Pacific, Kuiter and Debelius (2009).

Our records:

Australia: Flynn Reef, Lizard Island, Ribbon Reefs 3 & 10, Lena Reef, Low Isles, St Crispin Reef, Outer Whitsunday Reefs,

Papua New Guinea; Talili Bay & Kimbe Bay in New Britain, Hermit Islands.

Solomon Islands; Ghizo Island, Guadalcanal, Kolombangara Island, Maravagi, Soghonara Island, Peava, Russell Islands.

Vanuatu; Ambae Island, Bokissa Island.