Tuatara: Volume 7, Issue 2, December 1958
A Key to the Families of New Zealand Amphipods*
A Key to the Families of New Zealand Amphipods*
The amphipods form an order of sessile-eyed Crustacea in which the great number of species is reflected by a striking variety of habitats ranging from the heights of mountain ranges to the greatest depths of the ocean. Yet the variety of morphological distinction is comparatively limited and so the classification is necessarily based on a complex of small morphological characteristics. There are certainly bizarre and weird species, but the great number of the several thousand species which have been described are of a morphological sameness conforming to three or four basic patterns, relieved in the littoral and pelagic species by an often startlingly beautiful body and eve coloration. This ephemeral beauty fades with the approach of the preservative bottle or, strangely enough, with adaptation to a supralittoral or terrestrial environment.
There are four sub-orders. The Cyamidea, called by some authors the Caprellidea, is comprised of the Cyamidae or whale-lice and the Caprellidae or skeleton shrimps. In both of these families the distinctive body shape has been achieved by reduction of segments and degeneration of appendages, with flattening of the body in the one case and rounding and elongation in the other. The Hyperiidea are large-eyed and usually transparent or violet-reddish pelagic amphipods. The Gammaridea, which are the most numerous and diverse in form, are represented particularly in the tidal and bottom regions of the ocean, but are also found in fresh water and on land. The last sub-order, the Ingolfiellidea, has not as yet been recorded from New Zealand. Although long and cylindrical in general appearance like the skeleton shrimps, the Ingolfiellidea are clearly distinguished from all other Amphipoda by the complete separation of the eyelobes from the head and by the pleopods which consist of moderately small, almost triangular plates. In addition, in both gnathopods, the fifth segment has been developed as a hand and the sixth and seventh together form a combined dactylos or claw (Hansen 1903). Altogether, some 48 families and more than 200 species of amphipods have been recorded from New Zealand, its surrounding waters and outlying islands.
Apart from studies on the classification, little work has been done on the group in New Zealand. The first species from New Zealand were described page 72 by Milne-Edwards in his ‘L'Histoire -Naturelle des Crustacés’, and some years later Dana published the ‘Results of the United States Exploring Expedition ‘(1853, 1855). The Crustacean section of this may be found in the Turnbull Library. New species have been added by the reports of the Challenger, Scotia, Southern Cross, Terra Nova and Discovery Expeditions; by Dr. Th. Mortensen's 1914-1916 Expedition to the Subantarctic Islands and by Dr. Kohl-Larsen's expedition to the Subantarctic Islands and to South Georgia. ‘The Subantarctic Islands of New Zealand’ contains a large section on amphipods collected and examined by Charles Chilton. An 1876 work by E. J. Miers, ‘Catalogue of the Stalk- and Sessile-Eyed Crustacea of New Zealand’, summarised all previous knowledge of New Zealand amphipods and, although most of it is not original, it is a valuable and somewhat more accessible collation of earlier work.
Apart from these reports, a paper by Powell (1874), and two small papers by Kirk (1879) in the Transactions of the New Zealand Institute, the major work on the group in New Zealand was done by G. M. Thomson and Charles Chilton. Their papers are to be found in the Transactions of the New Zealand Institute, the Annals and Magazine of Natural History, the Journals of the Linnean Society of London and New South Wales, and several other and often obscure journals. As a result, although there have been few workers on the New Zealand fauna, some of the papers are very hard to obtain. More recently, several papers by the author have attempted to summarise and bring up-to-date our knowledge of the New Zealand amphipods.
Because of the great number of species and the system of classification, the amphipods are something of a specialist's group and they will probably always remain so. Nevertheless, it is possible without much trouble to track down specimens at least to family level and, after some acquaintance, to recognise many of the families on sight. At the generic level, unless the group has been recently and well covered in a general survey, difficulties in identification wall quickly pile up, especially in regard to available literature in New Zealand.
Representative types of amphipods. 1. Family Acanthonotozomatidae. 2 Family Caprellidae. 3. S.O. Hyperiidea— Family Platyscelidae. 4. Family Cyamidae. 5. Family Corophiidae. 6. Family Lysianassidae. 7. Family Lysianassidae. 8. S.O. Hyperiidea— Family Vibiliidae.
Identification is based on external morphological characteristics. Unless a person is familiar with the group already, it is necessary to dissect off the animal's appendages fairly extensively. Almost all of the external characteristics which could possibly be used for identification are used, and the mouthparts are especially important. For accurate identification it is necessary to check in detail antennae, rostrum (if present), mouthparts (epistome, upper and lower lip, mandibles, first and second maxillae, and maxilliped), all seven pairs of leg appendages (generally reckoned as first and second gnathopods and first to fifth peraeopods), gills, epimeral plates, pleopods, uropods and telson. This is in addition to any peculiarities of general body shape.
Some of these terms call for explanation. The mouthparts are best explained by the figures— they lie beneath one another in the order given above. The epistome is a structure overlying the upper lip, sometimes fused with it, sometimes deeply separated from it, often in the vertical plane whereas the upper lip lies in the horizontal plane. The mandibles and first maxillae may have quite long, but usually slender, ‘palps’ attached to them or they may lack palps entirely. The maxilliped is made up of an inner and outer plate and a palp (lacking in the Hyperiidea). The maxilliped palp segments are named in the same manner as the leg appendages, i.e. basos (second), ischium (third), merus (fourth), carpus (fifth), propod (sixth), and dactylos (seventh).
Generalised amphipod and appendages. Gn. = gnathopod; Pr. = peraeopod. Numbers correspond to appendage segments as shown in diagram of Gnathopod 2 except for Generalised Amphipod where 1-7 identify sideplates 1-7; 1′-2′ identify legs 1-2 (gnathopods 1-2); 3′-7′ identify legs 3-7 (peraeopods 1-5); and 5″-7″ identify basal segments (basos) of peraeopods 3-5.
The segments bearing the pleopods are usually known collectively as the pleon. Apart from the pleopods themselves, which have considerable diagnostic value in the Talitridae where they may be greatly modified or even reduced to vestigial stumps, importance is attached to the shape of the protective plates produced down on each side from the body and corresponding somewhat to the sideplates. These are usually known as ‘epimeral plates’. The three uropods and the telson present less difficulty in nomenclature. Other terms used are explained by the diagrams which have been somewhat generalised to show clearly a type rather than refer to a specific genus or animal.
Terrestrial species are best collected by the Berlese funnel method; that is, by heating leafmould in a special funnel with a gauze platform which allows animals to pass through the gauze and down the neck of the funnel into the preservative below but prevents the leafmould from accompanying them. A heating element in the lid or a lid with water-jacket supplies the necessary stimulus to movement. Pelagic species are usually collected in plankton nets although they may be taken when attracted to a strong light at night or more rarely in shoals cast on the beach.
Generalised Appendages. 1— Maxilliped (o.p. = outer plate; i.p. = inner plate). 2— Maxilliped propod and dactylos of a different species. 3 and 4— Degenerate types of maxilliped without palps, found in Hyperiidea. 5— Lower lip (o.l. = outer lobe or plate). 6— Lower lip of type with notched outer lobes or plates (i.l. = inner lobe or plate). 7— Maxilla 1 (i.p. = inner plate; o.p. = outer plate). 8— Maxilla 2. 9— Upper lip and epistome viewed from in front. 10— Upper lip and epistome of species with incision between them, viewed from side. 11—Upper lip and epistome of species where they are less distinctly separated, viewed from side. 12— Mandible. Enlarged portion shows cutting edge, accessory plate (a. plate), spine row and molar process. 13— Telson with rounded end, ‘entire’. 14— Telson of deeply cleft type. 15— Epimeral plate 3 of type with produced posterdistal angle. 16— Pleopod. 17— Uropod with single ramus. 18— Uropod with two rami, one uncinate. 19— Uropod with two normal rami. 20— Urosome of Hyperiid showing telson and uropods 1-3.
Alcolhol, 70% or 95%, is probably the best preservative. If the specimens are required soft a drop of glycerine will help although for systematic purposes the brittleness imparted by alcohol makes dissection with needles much easier. It has the disadvantage that appendages are liable to breakage before examination but this can usually be prevented by careful handling. Formalin has the distinct advantage of preserving colours for a considerable time. As a general rule, colour is not of great importance in classification in the amphipods but there are a few species for which it is important, and these do not usually lose their pigmentation pattern in either alcohol or formalin although the colour of the pigment may change in alcohol.
The keys which follow treat the Families of Cyamidea and of Gammaridea. The Hyperiidea have been treated in a recent paper elsewhere (see No. 11 in list of papers following key). As a general guide, the following pointers are useful. All terrestrial and supralittoral hoppers belong to the Family Talitridae, and species of this family are particularly abundant in New Zealand, especially in leafmould— the Crustacea at the bottom of the garden. These species belong to the genera Talitrus, Talorchestia and Orchestia. Fresh-water species in New Zealand are likely to belong to the Gammaridae (Phreatogammarus, Melita, Paracrangonyx), Talitridae (Chiltonia), Calliopiidae (Paracalliope, Paraleptamphopus), Pontogeneiidae (Paramoera) or Corophiidae (Paracorophium).
The keys are based on those given by Stebbing (1906) and Barnard (1940). Stebbing's monograph on the Gammaridea in the ‘Das Tierreich’ series, whilst obviously not including the great bulk of systematic work done since, is still the major work in the group but it is not easy to obtain. Because of its importance, it is worth mentioning that copies are held at Canterbury University College (Chilton Collection) and at Portobello Marine Biological Station. The first volume of the Challenger report is also very valuable; there Stebbing summarises every paper up to 1887 dealing with the group, and gives in full or in precis many otherwise unobtainable descriptions.
Key to the New Zealand Families of Amphipoda Cyamidea
(The numbers in brackets after the family name refer to papers in the list following the key.)
|1||Body elongate, cylindrical; both pairs of antennae well-developed (free-living among weed, coral, etc.; ‘skeleton shrimps’, pl. 1, fig. 3.||CAPRELLIDAE|
|Body short, depressed; second antennae rudimentary (ectoparasitic on whales, pl. 1, fig. 4).||CYAMIDAE (1)|
Key to the New Zealand Families of Amphipoda Gammaridea
(The remarks in brackets refer only to the New Zealand species, and the number of species in each family is given only as a guide to the importance of the family and the possible ease with which specific determination may be made.)
|1||Antenna 1, first segment stout, accessory flagellum present; mandible cutting edge almost smooth, with palp; gnathopod 2 with third segment elongate (second largest New Zealand family, about 20 species, bottom-dwelling, lobed peraeopod 2 sideplate is characteristic, pl. 1, figs. 6, 7).||LYSIANASSIDAE|
|These characters not combined.||—||2|
|2||Body plump; antenna 1 with accessory flagellum; mandible without molar and without palp (3 species).||STEGOCEPHALIDAE (12)|
|These characters not combined.||—||3|
|3||Body compressed or cylindrical. Pleon segments 5 and 6 generally reduced or absent. Antennae without accessory flagella. Mandible without palp, molar vestigial or wanting. Telson cleft or apically incised 2 species).||PROPHLIANTIDAE|
|These characters not combined.||—||4|
|4||Head tapering, truncate; eyes when present simple, usually four; antenna 1 without accessory flagellum; telson more or less cleft (2 species, bottom-dwelling).||AMPELISCIDAE|
|These characters not combined.||—||5|
|5||Antenna 1 with accessory flagellum; mandible palp normal; prps. 3-5 with segments expanded for burrowing (strongly setose and spinose peraeopods, and hooded rostrum over antennae in the Phoxocephalidae are very distinctive for these families).||—||6|
|These characters not combined.||—||7|
|6||Pr. 4 not greatly longer than pr. 5 (2 species.).||HAUSTORIIDAE|
|Pr. 4 greatly longer than pr. 5 (6 species).||PHOXOCEPHALIDAE (3)|
|7||Upper lip incised; maxilliped normal; uropod 3 biramous; telson elongate and entire (7 species).||AMPHILOCHIDAE (12)|
|These characters not combined.||—||8page 80|
|8||Antenna 1 without accessory flagellum; maxilla 1 palp has second joint enormously expanded to form curved plate; upper lip asymmetrical. (1 species, deep-water).||STILIPEDIDAE(10)|
|These characters not combined.||—||9|
|9||Antenna 1 without accessory flagellum; maxilliped more or less abnormal; telson entire.||—||10|
|These characters not combined.||—||14|
|10||Gnathopod 1 chelate (1 species, commensal in ascidians).||LEUCOTHOIDAE|
|Gnathopod 1 not chelate.||—||11|
|11||Uropod 3 biramous (2 species)||COLOMASTIGIDAE (6)|
|Uropod 3 uniramous.||—||12|
|12||Mandible with palp (2 species).||METOPIDAE|
|Mandible without palp.||—||13|
|13||Maxilliped outer plate obsolete (4 species).||STENOTHOIDAE|
|Maxilliped with both plates developed (1 species).||PHLIANTIDAE|
|14||Mandible with molar weak or wanting; telson more or less divided.||—||15|
|These characters not combined.||—||17|
|15||Maxilliped inner plate well developed (3 species, pleon dorsally toothed; pl. 1, fig. 1).||ACANTHONOTOZOMATIDAE (9)|
|Maxilliped inner plate small.||—||16|
|16||Gnathopods 1 and 2 simple (1 species).||PARDALISCIDAE (9)|
|Gnathopods 1 and 2 strongly subchelate (5 species).||LILJEBORGIIDAE (9)|
|17||Eyes, when present, dorsally contiguous or confluent; antenna 1 lacks accessory flagellum; third segment of mandibular palp large; pr. 5 much longer than pr. 4; telson entire (3 species).||OEDICEROTIDAE|
|Eyes, when present, lateral; other characteristics not combined as above.||18|
|18||Sideplate 4 usually excavate behind; pr. 1 and 2 not glandular; telson variable; animal usually not domicolous.||—||19|
|Sideplate 4 usually not excavate behind; pr. 1 and 2 glandular; telson entire; animal usually domicolous (living in self-made mud or sand tubes).||26|
|19||Mandible with palp.||—||20|
|Mandible without palp.||—||25|
|20||Telson variable, usually cleft; antenna 1 usually with accessory flagellum (marine, brackish and fresh-water, about 15 species).||GAMMARIDAE (4)|
|21||Rostrum weak (marine and fresh-water, 8 species).||CALLIOPIIDAE|
|Rostrum well marked.||—||22|
|22||Sideplates 1-4 rounded; antenna 1 longer than antenna 2 (1 species).||PLEUSTIDAE|
|Sideplates 1-4 angular; antenna 1 shorter than antenna 2 (1 species).||PARAMPHITHOIDAE (15)|
|23||Pleon segments 5 and 6 coalesced (2 species).||ATYLIDAE|
|Pleon segments 5 and 6 not coalesced.||—||24|
|24||Gnathopods 1 and 2, hands powerful (2 species).||EUSIRIDAE page 81|
|Gnathopods 1 and 2, hands not powerful (about 10 species, fresh-water and marine).||PONTOGENEIIDAE|
|25||Uropod 3, both rami well developed (3 species, pleon of 2 of them strongly toothed, 1 often commensal in ascidians).||DEXAMINIDAE|
|Uropod 3, 1 ramus very small or wanting (largest N.Z. family, 35 species, terrestrial especially in leafmould, marine and fresh-water, pl. 2).||TALITRIDAE (2, 8, 13, 14, 16)|
|26||Uropods 2 and 3, 1 or other wanting or rudimentary (2 species).||PODOCERIDAE|
|Uropods 2 and 3 well developed.||—||27|
|27||Pleon compressed, uropod 3 biramous (pl. 3, fig. 19; except Grandidierella).||—||28|
|Pleon usually depressed; uropod 3 uniramous (pl. 3, fig. 17; except Chelura).||—||31|
|28||Uropod 3 not uncinate.||—||29|
|Uropod 3 uncinate (pl. 3, fig. 18).||—||30|
|29||Gnathopod 1 larger than gnathopod 2 (3 species).||AORIDAE|
|Gnathopod 1 not larger than gnathopod 2 (10 species).||PHOTIDAE|
|30||Lower lip has principal lobes notched (pl. 3, fig. 6, 1 species).||AMPHITHOIDAE|
|Lower lip principal lobes not notched (3 species).||JASSIDAE|
|31||Antenna 2 flagellum not spatulate; uropod 3 uniramous, terete (or inner ramus very minute).||—||32|
|Antenna 2 with spatulate flagellum; uropod inner ramus minute, outer ramus foliaceous (1 species, wood-boring, pl. 1, fig. 5).||CHELURIDAE|
|32||Both gnathopods chelate (gnathopod 2 with third segment rather long (1 species).||SEBIDAE|
|Gnathopods not chelate (gnathopod 2 sometimes complexly subchelate, fifth segment prolonged); gnathopod 2 with third segment short (7 species, 1 from ocean depths, rest fresh-water, brackish or marine; common around wharf structures or buoys).||COROPHIIDAE|
BARNARD, K. H., 1930— Crustacea. Part XI - Amphipoda. British Antarctic (‘Terra Nova’) Expedition, 1910. Natural History Report. Brit. Mus. (Nat. Hist.), 1930, pp. 307-454.
BARNARD, K. H., 1932— Discovery Reports. Amphipoda. Vol. V: 1-326.
BARNARD, K. H., 1940— Contributions to the Crustacean Fauna of South Africa XII. Further Additions to the Tanaidacea, Isopoda and Amphipoda together with Keys for the Identification of the Hitherto Recorded Marine and Freshwater Species. Ann. S. Afr. Mus. vol. 33(5); 381-543, text-figs. 1-35.
CHEVREUX, E., FAGE, L., 1925— Amphipodes. 9. Faune de France: 1-488.
CHILTON, C., 1909— Crustacea. The Subantarctic Islands of New Zealand. Vol. 2: 601-671.
DANA, J. D., 1853 and 1855— The Crustacea: United States Exploring Expedition during the years 1838, 1839, 1840, 1841, 1842 under the Command of Charles Wilkes, U.S.N. vol. XIII. Part 2. Amphipoda, pl. 54-69.
HALE, H. M., 1929— The Crustaceans of South Australia. Part 2. Handbooks of the Flora and Fauna of South Australia.
HANSEN, H. J., 1903— ‘The Ingolfiellidae, fam. n., A New Type of Amphipoda.’ J. Linn. Soc. Lond. Zool., 24(188): 117-133, pls. 14-15.
MIERS, E. J., 1876— Catalogue of the Stalk and Sessile-Eyed Crustacea of New Zealand. Pp. 1-136, pl 1-3.
STEBBING, T. R. R., 1888— Amphipoda. Report ‘Challenger’ Expedition. Vol. 29.
STEBBING, T. R. R., 1906— Amphipoda Gammaridea. Das Tierreich. Vol. 21: 1-806.
STEPHENSON, K., 1927— Crustacea from the Auckland and Campbell Islands. Vidensk. Medd. Dansk. naturh. Foren. vol. 83: 289-390.
STEPHENSON, K., 1938— Amphipoda, Tanaidacea und Pycnogonida. Zoologische Ergebnisse der Reisen von Dr. Kohl-Larsen nach den Subantarktischen Inseln bei Neu-Seeland und nach Sud-Georgien. Senckenbergiana vol. 20 (3/4): 236-263.
Recent New Zealand Literature
Various families and genera of New Zealand amphipods have been revised recently by the author in the series. ‘Studies on the New Zealand Amphipodan Fauna’, in the Transactions of the Royal Society of New Zealand.
|1.||The Family Cyamidae. 1952. Vol. 80(1): 63-68.|
|2.||The Family Talitridae. 1954. Vol. 81(4): 563-577.|
|(Key to family; key to species of Chiltonia.)|
|3.||The Family Phoxocephalidae. 1954. Vol. 81(4): 579-599.|
|(Key to family; key to species of Heterophoxus and Phoxocephalus.)|
|4.||The Family Gammaridae. 1954. Vol. 81(4): 601-618.|
|(Key to family; keys to species of Elasmopus, Maera and Phreatogam marus.)|
|5.||The Family Amphithoidae. 1954. Vol. 81(4): 618-626.|
|(Key to family.)|
|6.||The Family Colomastigidae. 1954. Vol. 82(2): 419-429.|
|(Key to species.)|
|7.||The Family Corophiidae. 1954. Vol. 82(2): 431-460.|
|(Key to family; key to species of Corophium, Paracorophium.)|
|9.||The Families Acanthonotozomatidae, Pardaliscidae and Liljeborgiidae. 1954. Vol. 82(3): 763-802.|
|(Key to Family Acanthonotozomatidae and species of Panoploea and Iphimedia; key to Family Liljeborgiidae and species of Liljeborgia.)|
|10.||The Family Stilipedidae (Not Tironidae), 1954. Vol. 82(3): 803-811. (Describes Stilipes sanguineus as Cacao sanguineus.)page 83|
|11.||The Sub-Order Hyperiidea. 1955. Vol. 83(1): 119-194.|
|(Keys to N.Z. Families and species of Hyperiidea.)|
|12.||The Families Stegocephalidae and Amphilochidae. 1955. Vol. 83(1): 195-221.|
|(Keys to Family Stegocephalidae and species of Andaniotes; Keys to Family Amphilochidae and species of Neocyproidea, Amphilochus and Gitanopsis.)|
|13.||The Family Talitridae, 1956. Vol. 84(2): 359-389.|
|(Key to species of Talorchestia.)|
|14.||The Family Talitridae. 1957. Vol. 84(4): 903-933.|
|(Keys to species of Hyale and Allorchestes.)|
|16.||The Family Talitridae. 1957. Vol. 85 (1): 149-199.|
|(Key to species of Orchestia.)|
|As well as these, there are two papers in other journals:—|
|8.||The Family Talitridae. 1955. Pacific Science, 9(2): 144-157.|
|(Key to species of Talitrus.)|
|15.||The Family Paamphithoidae. 1957. Zool. Publ. from Victoria University College. No. 21.|
|It should be noted that these are not the full titles of the papers in this series, and that some of the keys are for the New Zealand genera and species only.|
* Part of this work was written at Portobello Marine Biological Station during the tenure of a Nuffield Research Grant.