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Zoology Publications from Victoria University of Wellington—Nos. 78, 79 and 80

Family Hippolytidae

Family Hippolytidae

Seven species have been recorded from the New Zealand region: Alope spinifrons (H. Milne-Edwards, 1837), Bathyhippolyte yaldwyni Hayashi & Miyake, 1970, Hippolysmata morelandi Yaldwyn, 1971, Hippolyte bifidirostris (Miers, 1876), H. multicolorata Yaldwyn, 1971, Nauticaris marionis Bate, 1888, Tozeuma novaezealandiae Borradaile, 1916. Larvae of five of these species have been described by Packer (1983). The remaining two species are Hippolysmata morelandi, a shallow water species from northern New Zealand, and Bathyhippolyte yaldwyni, which has been taken in deep water off the east cost of the South Island.

The eggs of B. yaldwyni are large and few in number, and so this species almost certainly has abbreviated development, and the larvae page 8should easily be distinguished from those of the other New Zealand Hippolytidae.

Larvae of Hippolysmata morelandi should also easily be identified. Known larvae of the genus Hippolysmata are characterised by the enormous size and oar-like propodus of pereiopod 5 (Fig. 3C). Gurney (1937) summarised larval characters of this genus.

Only the zoea 1 of Nauticaris marionis is known, and no other larvae of the genus have been described. Hence, without information on later larvae of this genus, it is not possible to construct a key to larvae of the New Zealand Hippolytidae. Therefore, in place of such a key, characteristic features of the known New Zealand hippolytid larvae are provided below.

There is such a wide variation of form among larvae of this family that it is difficult to provide a list of characters by which they can be recognised as a group. The following combination of characters is shared by the larvae of all New Zealand species except those of Hippolysmata morelandi for which characters 1, 3 and 7 do not apply:

Hippolytid larval characters

1.Eyestalks short, cylindrical rather than tapering proximally.
2.Rostrum extends beyond eyes (except in late larvae of Alope), without spines.
3.Maxillule with outer plumose seta and with distal lobe of endopod bearing three setae (Fig. 3J).
4.Exopod of maxilla in mid- and late larvae with proximal extension, and with distal margin almost straight rather than smoothly rounded, always with setae on outer proximal margin (Fig. 3K).
5.Maxillipeds 2 and 3 with flexible rather than spiniform setae (e.g. Fig. 3I, cf. Fig 4E).
6.Both pereiopods 1 and 2 with a well formed chela in late larvae.
7.Antennules not separated at base by more than width of one of them (Fig. 3D).
8.Antennal exopod distally segmented in early larvae (Fig. 3E).
9.Never more than 8+8 telsonic setae.

Diagnostic characters of New Zealand Hippolytidae larvae

Alope spinifrons (Fig. 3G)

Carapace with one pair of anterolateral spines in zoea 1, and two pairs from zoea 2 onward (of which the more dorsal is as long as the antennal protopod in late larvae), with supraorbital spines from zoea 2 page 9onwards; abdominal somites 1-5 without spines; pereiopods 1-4 with exopod bearing six setae when first developed but with up to 12 setae in late larvae; pereiopods 3-5 raptorial in form and pereiopod 5 shorter than pereiopods 2-4 when all developed.

Hippolyte bifidirostris and H. multicolorata (Figs. 3A, B)

Carapace with 3-5 pairs of anteroventral spines and one pair of anterolateral spines; region above latter minutely serrated; also with supraorbital spines from zoea 3; abdominal somite 5 with posterolateral spines, also with small posterodorsal spines in H. multicolorata only; pereiopods 1-2 with exopod, 3-5 poorly segmented and probably not functional; exopods of pereiopods and maxillipeds with no more than six setae.

Nauticaris marionis (Figs. 3D-F)

Only zoea 1 known; carapace with one pair of anterolateral spines; abdomen with small posterodorsal spines on somite 5 and no other spines; antennal endopod almost twice length of exopod, with small accessory seta, and with long tapering distal portion bearing two rows of widely spaced spines.

Tozeuma novaezealandiae (Fig. 3H)

Long and slender larvae with very prominent, forward-pointing dorsomedial spine on somite 3; also with strong posterolateral spines on abdominal somite 5.