Records of the Western Australian Museum 19: 243-257 (1999). Copepods from ground waters of Western Australia, IV. Cyclopids from basin and craton aquifers (Crustacea: Copepoda: Cyclopidae) l l P. De Laurentiis , G.L. Pesce and W.F. Humphreys2 1 Dip~rtimento di Scienze Ambientali, University of L'Aquila, Via Vetoio, 1-67100 L'Aquila, Italy . Western AustralIan Museum, Francis Street, Perth, Western Australia 6000, Australia Abstract - Halicyclops rochai sp. novo is described from a near-coastal aquifer m the Robe RIver bas1O. Dzacyclops reldae sp. novo and Diacyclops einsfei sp. novo are descnbed from the MJilstream aquifer in the western Fortescue Valley on the Pilbara craton. Records with large range extensions are given for Paracyclops fimbrlatus (Flscher, 1853), Dzacyclops 1111mphrcysi Pesce and De Laurentlls, 1996, !v1lcrocyclops varicans (GO. Sars, 1863), Metacyclops mortoni Pesce, D~ Laurentns and Humphreys, 1996 and Mesocyclops brooksi Pesce, De Laurentlls and Humphreys, 1996. The description of D. humphreysi is amplJfIed. .Halicyclops roChal sp. novo belongs to a Tethyan group of species and IS Similar to Haflcyclops sp. novo Rocha et al. from the Yucatan Peninsula, Mexico. As such, it accords with the biogeographic affinities of non-copepod elements of the fauna. INTRODUCTION exceeding the low annual rainfall (c. 350 mm) by Arid northwestern Australia is proving to contain about an order of magnitude, and is characterised a diverse subterranean fauna in both terrestrial by very high summer temperatures. The detailed (Humphreys 1993c) and aquatic systems environment is unknown, but water chemistry data (Humphreys 1993a; papers in Humphreys 1993b). are available for a number of sites. The stygofauna in particular contains many Millstream - The Millstream aquifer, in Tertiary remarkable disjunct lineages in both anchialine (e.g. valley fills of palaeodrainage channels on the Yager and Humphreys 1996) and freshwater Pilbara craton, is in a karstic groundwater calcrete aquifers (Poore and Humphreys 1998), the and freshwater (TDS 864 mg L-I [s.e. 128.8, n=6]­ existence, extent and affinities of which are only just raw data from pump tests in Barnett and being explored (Humphreys, in press a, in press b). Commander 1985) with a pH of 7.4±0.09. The Cyclopoid copepods recently collected from the characteristics of the Millstream aquifer and its near-coastal areas of northwestern Australia have geological context have been discussed at length by included the genera Metacyclops Kiefer, 1927 sensu Poore and Humphreys (1998), together with the Lindberg, 1961, Mesocyclops G.O. Sars, 1914, potential great age of the associated fauna (see also Microcyclops Claus, 1893, Apocyclops Lindberg, 1942, Humphreys 1993a, in press b). Forty-six locations were sampled in the Millstream aquifer, of which Haficyclops Norman, 1903 and Oil/CYclops Kiefer, 20 yielded fauna of some type (16 piezometers, 1927 (Pesce, De Laurentiis and Humphreys 1996a, three wells, one water bore). 1996b; Pesce and De Laurentiis 1996). These studies The associated fauna in the aquifer includes a greatly extended the range of some species and new genus of Spelaeogriphacea, the first record of revealed a number of new species, some of which the order in Australasia (Poore and Humphreys are restricted to groundwaters in this arid region. 1998), as well as other elements of a clearly The present paper examines material from the Gondwanan fauna, inter alia a genus of water mites Pilbara craton (Millstream), a region of prolonged previously known only from India (Harvey 1998), stability and not inundated by the sea since the syncarids (Bathynellacea), phreatoicid isopods, Proterozoic (Hocking et al. 1987), as well as phreodrilid oligochaetes, and also hydrobioid collections made on the coastal plains of Mesozoic gastropods, ostracods and crangonyctoid arnphipods. age or younger (Yarraloola and Mardie Stations) Mardie and Yarraloola Stations, Carnarvon Basin that fringe the craton. Some collections from - The aquifers are in gravel fans resulting from the groundwaters in the Perth Basin are included. discharges through water gaps respectively of the Fortescue and Robe Rivers from the Pilbara craton onto the coastal plain of the Carnarvon Basin HABITAT AND ASSOCIATED FAUNA (Commander 1994a, 1994b). They lie The area is arid with the annual evaporation unconformably on Precambrian bande'd iron 244 P. De Laurentiis, G.L. Pesce, W.F. Humphreys aquifers in Quaternary-Late Tertiary deposits of the Perth Basin (Davidson 1995), north of the Swan River and bordering the Yilgarn craton. The water was essentially fresh and mostly distant from surface drainage channels. The general fauna included ostracods and bathynellid syncarids, harpacticoid copepods, oligochaetes, microturbellia and nematodes. Outflows from the water mounds to the west of the sample area support a rootmat community that is rich in fauna in shallow cave environments (Jasinska, et al. 1996). All the copepods mentioned herein came from a restricted area of the Gnangara Mound (South) in an area of upward leakage from the Mirrabooka sandstone aquifer, which is of Cretaceous age, with salinity less than 500 mg L-I TDS and the only associated fauna comprised ostracods and oligochaetes. Yule and De Grey Rivers - respectively in the Pilbara Province (Whincup 1967) and the Canning Basin (Davidson 1975). There samples were taken from unused bores in the current freshwater production borefield (Water Corporation) located in these sand aquifers. Samples were taken at 18 locations (13 in the Yule) and the associated fauna included ostracods, amphipods (Melitidae) and bathynellid syncarids. Ocean \j Port Hedland and Cossack -A single sample was taken at each site from early historical wells. Associated fauna includes ostracods. 500 km MATERIAL AND METHODS Map! Sampling locations mentioned in the text. 1, In October 1996 a brief reconnaissance survey of Millstream; 2, Mardie Station; 3, Yarraloola some groundwaters was conducted in northwestern Station; 4, Cossack; 5, Port Hedland; 6, Perth Basin. Millstream is on the Pilbara craton Australia. Groundwater was sampled with haul while Mardie and Yarraloola Stations lie to its nets (350 llm mesh size) predominantly from west, in the Camarvon Basin. groundwater monitoring bores - some samples were taken from pastoral wells and from river gravels by the Karaman-Chappuis method - in aquifers along the Western Fortescue Plain formation (Proterozoic schist in the case of the Robe (Millstream) and the lower Fortescue (Mardie Valley) and basalt, Cretaceous conglomerate and Station) and Robe Rivers (Yarraloola Station: Map siltstone, and on Tertiary pisolite and limestone 1). Minor sampling was undertaken at Cossack, Port (ibid.). Groundwater salinity ranges from 345 mg Hedland, and aquifers in the De Grey and Yule L'! (TDS) close to the river to 1200 mg L-! near the Rivers. Some samples from the Perth Basin were tidal flats where there is a saltwater interface (ibid.). also examined (Map 1). Samples were taken from 35 bores and pastoral All samples were sorted while alive under a wells in two groundwater assessment borefields. dissecting microscope, preserved in 70% alcohol The fauna of these aquifers includes elements of the and assigned a field number (BES number). Tethyan fauna found on the Cape Range peninsula Permanent mounts were made in commercial and Barrow Island (Humphreys 1993a, in press a) polyvinyl-Iactophenol medium. Dissected including atyid shrimp, cirolanid isopods and specimens were drawn at magnifications of 400x thermosbaenaceans, as well as diverse amphipods and 1000x, the latter using an oil immersion lens (Paramelitidae, Bogidiellidae: J. Bradbury, pers. and "camera lucida" mounted on a Leitz Laborlux comm. 1997; Bradbury and Williams 1997), D phase-contrast microscope. Type material is ostracods, bathynellid syncarids, halacarid mites, deposited in the Western Australian Museum hydrobioid gastropods and microturbellarians. (WAM). Perth Basin - Samples were taken from a number Terminology applied to body and appendages is of groundwater monitoring bores in unconfined according to Huys and Boxshall (1991). Cyclopids from basin and eraton aquifers 245 SYSTEMATICS first endopodal segment; endopod segment 1 with 1 seta, segment 2 with 5 inner setae, 7 apical setae, Family Cyclopidae Burmeister, 1834 emend. and 2 rows of cilia on outer margin. Dana,1846 Labrum (Figure 9) with laterally serrate distal margin and row of 14 rounded teeth midway along Subfamily Halicyclopinae Kiefer, 1927 margin, the outer ones stouter; paired transverse Genus Halicyclops Norman, 1903 rows of spinules on anterior surface, rows of smaller spinules on posterior surface. Halicyclops roc1zai sp. novo Paragnaths (Figure 8) are simple lobes bearing Figures 1-21 patches of fine setules and spinules, and 3 well developed pectinate setae. Material Examined Mandible (Figure 1) with coxal gnathobase armed Holotype with 8 sharp teeth, 1 pectinated element and 2 « (WAM C 24171), bore 4A, Yarraloola Station, dorsal plumose setae; transverse row of 3 long Robe R, Western Australia, Australia (BES 4061), spinules implanted subdistally on cutting blade. 21°34'S, 115°51'E, 24 October 1996, W.F. Humphreys. Palp represented by 2 unequal setae implanted directly on coxa. Pa ra types Maxillule (Figure 3) consisting of praecoxa and 2­ Australia: Western Australia: 1 d, 1 juv. (WAM segmented palp. Praecoxal arthrite armed with 4 C 24172), Two Mile Well, Mardie Station, Fortescue spines, and 7 elements on inner