A Preliminary Survey of the New Zealand Crustacea Decapoda Natantia with an Appendix on the Reptant Genus Nephrops

Abstract

Seventeen species of the 58 recorded are described or diagnosed. Ten species, Aristaeomorpha foliacea, Sergestes sp., Sergestes cf. phorcus, Pasiphaea sp., Notostomus westergreni, Hippolyte n.sp., Ogyrides n.sp., Campylonotus rathbunae, Periclimenes (Periclimenes) sp. and Prionocrangon n.sp. are new records for this region. Four species are recorded for the first time since their description, Oplophorus novae-zeelandiae, "Pandalus" magnoculus, Chlorotocus novae-zealandiae and Angasia novae-zealandiae. An historical review of the New Zealand species is given followed by an alphabetical list of the synonyms in the literature and a list of eleven species incorrectly recorded from this region. Of the 26 non-indigenous species, 18 are also found in the Indo-Westpacific and 10, including the bottom dwelling Aegeon lacazei, in the Atlantic. Deep-water species e.g. Aristaeomorpha foliacea and Sergestes cf. phorcus, have been taken in this region at much shallower depths than in other parts of the world. The colour-patterns and chromatophores of 15 species are described. Campylonotus rathbunae has one colour (red), while Palaemon affinis has at least five (red, yellow, white, black and blue). Compound chromatophores are found in almost every species, compounded with black in Pontophilus australis and with red in every other species. Large blue chromatophores (up to 0.1 mm. in diameter) are described in Hippolyte n.sp. and H. bifidirostris. The freshwater Paratya curvirostris is found to be sexually dimorphic in colour-pattern, the males being much lighter. Variation in the rostral formula is described in detail for Palaemon affinis and generally for 7 other species. In P. affinis the rostrum, mostly longer but sometimes shorter than the carapace, has 5 to 10 dorsal teeth and 2 to 5 ventrals. The 1st dorsal tooth varies from subapical to posterior to the 2nd ventral tooth, a specimen of the latter extreme having been described as a synonym, P. quoianus. A small, but significant amount of unregenerated damage was seen and a number of individuals showing non-genetic variation are described as stages in regeneration of rostra after damage. In Aristaeomorpha foliacea the sexual dimorphism in rostral length, first described by Kemp and Sewell (1912), is here regarded as damage and regeneration stages only. Wide variation in the rostral formula appears more in species with long, slender rostra and many teeth than in species with short, stout rostra and few teeth, supporting the conclusion that non-genetic factors are active. The egg measurements of 12 species are given and these exhibit no relationship to the size of the species. Eggs from six species were hatched in the laboratory but the 1st larval stages are not described. Campylonotus rathbunae is the first species of the Family Campylonotidae found to be a protandric hermaphrodite. "Pandalus" magnoculus, does not belong in the genus Pandalus, and is not a protandric hermaphrodite. Ecological notes are given for some species. The littoral Betaeus aequimanus, Hippolyte n.sp., Alope spinifrons and Palaemon affinis are treated in greater detail than the others, as these occur in the one locality at Island Bay, Wellington, but each occupying a different habitat niche. The habits of these four species, as well as Periclimenes batei and Pontophilus australis, as observed in aquarium tanks, are described. A. spinifrons and P. australis are nocturnal, the latter being buried under the sand during the day. The first three males of Nephrops challengeri and one additional egg-bearing female have been taken in 80 to 300 fathoms since 1951. A list of the 19 species of Nephrops known up to 1951 is given and N. challengeri is compared to both N. thomsoni and N. sibogae, both close Indopacific forms. A prominent colour-pattern of bright red, brown and pink on white with blue eggs is described.