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Australian Biological Resources Study

Numbers of Living Species in Australia and the World

A.D.Chapman
Australian Biodiversity Information Services, Toowoomba, Australia
A Report for the Department of the Environment and Heritage, September 2005
ISBN (printed) 978 0 642 56849 6
ISBN (online) 978 0 642 56850 2

Online html version with updates (April 2007)


Detailed discussion by Group

Invertebrates

Hemichordata (hemichordates)

Burdon-Jones (1998) stated that there were 94 described species in 16 genera in the world, with many more undescribed, and 12 species in seven genera in Australia. Cameron (2004) lists 106 species for the World, Groombridge and Jenkins (2002) list c. 90 or 100, whereas Brusca and Brusca (2003) give only 85 species.

ABRS (2005a) now lists 17 species for Australia with an estimated 22 species in total. It would appear from the treatment by Burdon-Jones (1998) that at least three species are endemic to Australia. I have accepted the most recent figures of 106 for the world (Cameron 2004) and 17(22) (ABRS 2005a) for Australia.

World Described minimum World Described maximum World Accepted World Estimate Australia Described Australia Described % of World Described Australia Estimate Australia Endemic World Threatened47 Australia Threatened48 Australia Threatened % of World Threatened
85 106 106 110+ 17 16% 22 ~25%

Echinodermata (starfish)

Estimates of the number of echinoderms in the world vary from about 6 100 (Tangley 1997, Miyajima 2002) through 6 60049 (ABRS 2005b, Rich Mooi pers. comm.) to 7 000 (Wray 1999, Groombridge and Jenkins 2002, Brusca and Brusca 2003, Mulcrone 2005). The figure of 7 000 has been accepted here as being the most common figure used in most publications, however, the figure of 6 600 seems to be strongly justified on the breakdown of the individual Classes. The breakdown of estimates are: Crinoidea—600; Asteroidea—1 800; Ophiuroidea—2 000; Echinoidea—800; Holothuroidea—1 400 (ABRS 2005b, Rich Mooi pers. comm.).

Estimating the total number of species is a difficult exercise. The main problem appears to be the unknown of the deep waters, and the enormous potential of molecular studies to ‘discover’ new species50. The figure here is estimated by doubling known numbers for most classes, and adding an extra 20–25% for the Ophiuroidea and Holothuroidea which are ‘cryptic, diverse, relatively unstudied, and common in the deep sea’51.

Predictions place the number of Australian species at around 1 406 with 1 165 described (ABRS 2005a). The Australian Faunal Directory (ABRS 2005b) and others (Ponder et al. 2002) predict that there may be up to 2 000 species in Australian waters. I have seen estimates of endemism in Australia as high as 90% for southern waters and 15% for tropical waters (Ponder et al. 2002), but working through the currently published species (Rowe and Gates 1995), the figure comes out at around 31%.

World Described minimum World Described maximum World Accepted World Estimate Australia Described Australia Described % of World Described Australia Estimate Australia Endemic World Threatened52 Australia Threatened53 Australia Threatened % of World Threatened
6 100 7 000 7 000 ~14 000 1 165 16.6% ~1 406 31%
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Insecta (insects)

Estimates of the number of insects in the world vary from about 751 000 (Tangley 1997) through 800 000 (Nieuwenhuys 1999), 948 000 (Brusca and Brusca 2003), 950 000 (IUCN 2004) to more than 1 million (Myers 2001a). Groombridge and Jenkins (2002) provide the figure of 963 000 for insects plus myriapods. Estimates for the total numbers of insects vary widely from several million to around 8 million (Groombridge and Jenkins 2002). Calculations based on extrapolations from species of Coleoptera and Lepidoptera in New Guinea by Novotny et al. (2002) produced a figure of between 3.7 and 5.9 million for the total number of arthropods in the world. Some workers, however have estimated that there could be as many as 100 million beetles alone (Tangley 1997), but this would appear to be a gross over-estimation. The figure of 950 000 has been accepted here as being the most commonly cited figure in many recent publications, along with an estimate of about 4 million (May 2000) for the total number of species. As stated by Miller et al. (2002):

‘Current evidence from the major museum collections of sorted and labeled insect species, whether described or undescribed, does not support larger estimates, and insect taxonomists broadly concur from this that although there may be up to five million species of insect in the world, there are probably less than 10 million (Nielsen and Mound 2000). In a recent review, May (2000) settled on a best guess of four million species.’

The number of described species of Diptera in the world is 153 974 as of July 2006 and as reported on the Diptera Site (Thompson 2006). Detailed numbers of species in other orders is being worked on54.

The number of described species in Australia would appear to be around 80 000 (DEH in prep.) with the total number of species varying from about 95 000 (DEH in prep.) to nearly 205 000 (Yeates et al. 2003). Further discussions need to be held prior to determination of a reasonable estimate, so I have reported the range.

There are four listed threatened species of insect in Australia—one of which is undescribed. There is also one listed subspecies (DEH 2005a).

World Described minimum World Described maximum World Accepted World Estimate Australia Described Australia Described % of World Described Australia Estimate Australia Endemic World Threatened55 Australia Threatened56 Australia Threatened % of World Threatened
751 000 >1 million 950 000 4 000 000 ~80 000 8.4% ~95 000–204 743 unknown 559 (0.06%) 4 (0.005%) 0.7%
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Arachnida (spiders, scorpions, etc.)

Estimates of the number of described arachnids vary from 60 000 (Myers 2001a, Brusca and Brusca 2003), 70 000 species (Nieuwenhuys 1999), 74 000 (Groombridge and Jenkins 2002) to 75 000 (Hawksworth and Kalin-Arroyo 1995, May 2000). There do not seem to be many estimates for the total number of spiders in the world, however Coddington and Levi (1991) predicted that there may be as many as 170 000 species.

Perhaps the best way to determine the numbers of described species is to make a breakdown of the various orders. Spiders are probably the best known, and Platnick (2005) lists 38 834 described species of spider in The World Spider Catalog. One of the largest of the arachnoid groups includes the mites and ticks and here the numbers vary greatly. Hickman et al. (2004) estimated 40 000 described species with a total of 500 000 to 1 million. Halliday et al. (2000) estimated that there were 48 200 described species of Acarina and a total fauna of about 0.5 million. Walter et al. (1996) on the Tree of Life website estimated 45 000 described species and suggested that that may only be about 5% of the total species alive today. Other estimates from the 1960s and 1970s (see Haliday et al. 2000) vary from 17 500 to 30 000. Other Orders include Amblypygi (136—Harvey 2003), Opiliones (around 5 000 species—Myers 2001a; 6 000 species—Harvey 2002), Palpigradi (c. 78—Harvey 2003, to 80 species57), Pseudoscorpionida (>2 000 species58 and Myers 2001a; >3 239 species—Harvey 2002), Ricinulei (57 species—Amrine 2005), Schizomida (21959), Scorpionida (1 26060), Solifugae (1 088—Savary n.dat.; >1 075 species—Harvey 2003), Uropygi (>106 species—Fox 2005). Summation of these figures gives a total of over 95 500 described species, considerably higher than the estimates cited above, with estimates of the total number of species varying between 160 000 to about 1 million (Hawksworth and Kalin-Arroyo 1995). Hawksworth and Kalin-Arroyo (1995) accepted a working figure of 750 000 species.

Halliday et al. (2000) conducted an extensive literature survey of mites in Australia and concluded that there were about 2 700 described species and by extrapolating from recent revisions estimated that the total mite fauna in Australia may be in the order of 7 800. They then further suggested that this may be a gross under-estimation as many of the lesser known groups were likely to include many more species. Their final estimate for the total Australian mite species was in excess of 20 000 species.

The Australian Biological Resources Study (ABRS 2005a) reports numbers of described and estimated Australian species as shown in the following Table, except for the number of 7 800 for the estimated Araneae which comes from Halliday et al. (2000). Estimates for the total number of the described Australian Arachnid fauna varies from 5 666 (DEH in prep.) to 5 711 (ABRS 2005a) and for the total number of Arachnid fauna from 20 937 (using Halliday’s number for the Acarina) through 27 837 (using the ABRS figure for the Acarina) to 27 960 (DEH in prep.). No estimates of the percentage of Australian endemics has been found.

Order World Described World Estimate Australia Described Australia Estimate
Acari 48 200 ~100 000–500 000 2 399 11 500
Amblypygi 136 ~100 4 10
Araneae 38 384 50 000–70 000 2 871 7 800–15 000
Opiliones ~5 000 6 000 199 500
Palpigradi ~80   2 2
Pseudoscorpiones ~3 239   150 600
Ricinulei 57   0 0
Scorpiones 1 260 ~2 400 40 150
Schizomida 219   46 75
Solifugae 1 089   0 0
Uropygi 286   0 0
TOTAL 97 950 166 000–600 000 5 711 20 637–27 837

 

World Described minimum World Described maximum World Accepted World Estimate Australia Described Australia Described % of World Described Australia Estimate Australia Endemic World Threatened61 Australia Threatened62 Australia Threatened % of World Threatened
60 000 96 711 98 000 166 000–600 000 5 711 6.0% 27 960 unknown
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Myriapoda (millipedes and centipedes)

Brusca and Brusca (2003) gave an estimate of 11 460 described species of Myriapoda in the world.

Yeates et al. (2003) estimated the total number of described Myriapod species in Australia at 2 539. This is slightly higher than that estimated by ABRS (2005a).

Symphyla

Although little information could be obtained on this group, it would appear that there are about 200 described species of Symphyla in the world (ABRS 2005b). Brusca and Brusca (2003) estimated that there are 160 species.

ABRS (2005a) lists 26 species for Australia and estimates about 150 species in total. Yeates et al. (2003) provided a figure of 200 for the total number of species.

Diplopoda

Estimates of the number of described species of Diplopoda (millipedes) vary from 5 00063, through 8 000 (Brusca and Brusca 2003) to 10 000 (Geoffroy 2001). I have accepted the figure of 8 000 as given by Myers (2001b) and Brusca and Brusca (2003). Geoffroy (2001) estimates the total number of species at between 80 000 and 90 000.

Chilopoda

Estimates of the number of described species of Chilopoda (centipedes) vary from 2 500 (Hoffman 1982, Myers 2001c), 2 800 (Brusca and Brusca 2003) to about 5 00064. I have accepted the figure of 3 300 as provided in an application to the Global Biodiversity Information Facility (GBIF) for the development of A World Catalogue of Centipedes (Chilopoda) for the Web65.

Pauropoda

The number of described Pauropoda of the world is between 500 (Brusca and Brusca 2003) and 715 (ABRS 2005b), with 18 species described for Australia (50% of which are endemic), but with an estimated total number of greater than 500 (ABRS 2005b). I have accepted the ABRS figure of 715 for the world.

  World Described minimum World Described maximum World Accepted World Estimate Australia Described Australia Described % of World Described Australia Estimate Australia Endemic World Threatened66 Australia Threatened67 Australia Threatened % of World Threatened
1 120 200 200 unknown 26 13.0% 150 unknown 0 0
2 5 000 10 000 8 000 80 000–90 000 230 2.9% 2 000 unknown 0 0
3 2 500 5 000 3 300 unknown 131 4.0% 150 unknown 0 0
4 500 715 715 unknown 18 2.5% 500 50% 0 0
TOTAL 8 120 15 915 12 215 85 000+ 405 3.3% 2 800 unknown 0 0
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Crustacea (crabs, lobsters)

The estimated number of described species of Crustacea in the world varies from 30 000 (Myers 2001d), more than 30 000 (Ponder et al. 2002), 40 000 (with 38 000 marine species) (Hawksworth and Kalin-Arroyo 1995, May 2000, Groombridge and Jenkins 2002), 55 000 (Wikipedia 2005) 68 to 67 000 (Brusca and Brusca 2003). I have accepted the figure of 40 000 described species based on a detailed figure of 38 701 given by Abele (1982), and assuming that that figure would have increased somewhat since 1982. Abele’s figures were based on nine Cephalocarida, 821 Branchiopoda, one Remipedia, 9 589 Maxillopoda, 5 650 Ostracoda and 22 651 Malacostraca. Further information on individual taxa can be found in Crustacea.net coordinated by the Australian Museum (Lowry et al. 1999 onwards).

The estimated total number of world species is 150 000 (May 2000, Groombridge and Jenkins 2002) with a range of from 75 000 to 200 000 (Hammond 1995, Hawksworth and Kalin-Arroyo 1995). Brusca and Brusca (2003) stated that there could be from 5–10 times the number of described species giving a figure of 300 000–600 000 for their estimate. There are an estimated 7 130 described species in Australia out of a total estimated 9 500 species (DEH in prep.). There are seven listed threatened species in Australia (DEH 2005a).

World Described minimum World Described maximum World Accepted World Estimate Australia Described Australia Described % of World Described Australia Estimate Australia Endemic World Threatened69 Australia Threatened70 Australia Threatened % of World Threatened
30 000 67 000 40 000 150 000 7 130 17.8% ~9 500 unknown 429 (1%) 7 (0.1%) 1.6%
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Onychophora (velvet worms)

The number of described species of Onychophora would appear to be around 120, with estimates varying from about 70 (Hickman et al. 2004), 9071, 100 (Groombridge and Jenkins 2002), 11072 (Brusca and Brusca 2003) to about 120 (Monge-Najera 2000). Reid in the Australian Faunal Directory (ABRS 2005b) stated that there were 75 species in the Peripatidae and 90 in the Peripatopsidae making a total world described fauna of 165 species. This is the figure I have used here, even though it is considerably higher than the other estimates. Estimates for the total fauna include about 200 (Geoffroy 2001) and 220 (Brusca and Brusca 2003).

In Australia, ABRS (2005a) estimated that there are about 71 described species with perhaps another nine undescribed species.

Given that all species have very narrow ranges it has been suggested by Ponder, pers. comm. 2006, that most if not all species could be endemic.

World Described minimum World Described maximum World Accepted World Estimate Australia Described Australia Described % of World Described Australia Estimate Australia Endemic73 World Threatened74 Australia Threatened75 Australia Threatened % of World Threatened
70 165 165 ~220 71 43% ~80 unknown 0 0
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Mollusca (molluscs, shellfish)

Estimates of the number of described species of molluscs in the world vary from nearly 50 000 living species (Tangley 1997, Hickman et al. 2004), ? 70 000 (Hawksworth and Kalin-Arroyo 1995), 70 000–75 000 (with possibly more than 100 000) (Groombridge and Jenkins 2002), 93 195 (Brusca and Brusca 2003) to 120 000 (Ponder et al. 2002). Hawksworth and Kalin-Arroyo (1995) and Groombridge and Jenkins (2002) estimated a possible total of around 200 000 species, and May (2000) provided an estimate of about 120 000. I have accepted a figure of 70 000 described species (after Groombridge and Jenkins 2002) and a total of 120 000 species (after May 2000).

Estimates for Australia are approximately 8 700 described species out of a total of about 12 250 (DEH in prep.).

Endemism of about 90% is reported in the 2001 Australian State of the Environment Report (SOE), however Ponder et al. (2002) report that for marine taxa only about 10% of tropical species, and 95% of temperate species are endemic. The non-marine fauna is mostly endemic (at least 97%) according to Ponder (pers. comm. 2006).

There are two listed threatened molluscs in Australia (DEH 2005a).

World Described minimum World Described maximum World Accepted World Estimate Australia Described Australia Described % of World Described Australia Estimate Australia Endemic World Threatened76 Australia Threatened77 Australia Threatened % of World Threatened
50 000 120 000 70 000 120 000–200 000 8 700 12.4% ~12 250 90% 974 (1.4%) 2 (0.03%) 0.2%
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Annelida (segmented worms)

Estimates for the number of described species of Annelida in the world vary from 12 000 (Tangley 1997), 13 000 (with only about 8 000 reliable species) (Hutchings and Fauchald 2000), 13 500 (Myers 2001e), 15 000 (May 1998, Hickman et al. 2004), c. 16 000 (Groombridge and Jenkins 2002) to 16 600 (Brusca and Brusca 2003). Myers (2001e) reported about 10 000 species of Polychaeta, 3 000 species of Oligochaeta and about 500 species of Hirudinea, and a total of about 13 500 species.

An estimate for the total number of species is between 25 000 and 30 000 (Snelgrove et al. 1997 as reported by Ponder et al. 2002).

The number of described Australian species is about 2 300 out of an estimated total of about 4 230 (DEH in prep.). The percentage of endemics is unknown, but it is reported that southern Australia has about 67% endemism (Poore 1995).

There is one listed threatened worm species in Australia (DEH 2005a).

World Described minimum World Described maximum World Accepted World Estimate Australia Described Australia Described % of World Described Australia Estimate Australia Endemic World Threatened78 Australia Threatened79 Australia Threatened % of World Threatened
12 000 16 500 15 000 25 000–30 000 2 300 15.3% ~4 230 67% 30 (0.02%) 1 (0.04%) 3.3%
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Nematoda (nematodes, roundworms)

Estimates for the number of described species of Nematoda vary from around 12 000 (Myers 2001f, Hickman et al. 2004) to 20 000–25 000 (Groombridge and Jenkins 2002), fewer than 25 000 (Baldwin et al. 2000), and 25 000 (Hawksworth and Kalin-Arroyo 1995, Brusca and Brusca 2003). Estimates for the total numbers of species, however, are much larger with estimates ranging from 400 000 (Hawksworth and Kalin-Arroyo 1995, Groombridge and Jenkins 2002), about 500 000 (Myers 2001f, Hickman et al. 2004) to 500 000 to 1 million (Baldwin et al. 2000) and ‘several times’ their estimate of 25 000 (Brusca and Brusca 2003). Baldwin et al. (2000) state that ‘Although 4 000–5 000 marine nematode species have been named and described, full surveys of marine habitats probably will reveal many millions of previously unknown species’. They also provide references to estimates for the total number varying from 100 000 (Hawksworth and Kalin-Arroyo 1995) to as many as 10 million.

Estimates for the number of described Australian species vary from 1 200 (ABRS 2005a) to a recent estimate of about 2 060 (DEH in prep.). Estimates for the number of unknown species again vary from c. 30 000 (DEH in prep.) to 70 000 (ABRS 2005a). I have found no published estimates for the percentage of endemics.

World Described minimum World Described maximum World Accepted World Estimate Australia Described Australia Described % of World Described Australia Estimate Australia Endemic World Threatened80 Australia Threatened81 Australia Threatened % of World Threatened
12 000 25 000 <25 000 ~500 000 ~2 060 8% ~30 000 unknown 0 0
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Acanthocephala (thorny-headed worms)

Estimates for the number of described species in the world vary from more than 500 (Hickman et al. 2004), 850 (Wikipedia82), over 1 000 (Groombridge and Jenkins 2002) to 1 100 (Brusca and Brusca 2003).

Groombridge and Jenkins (2002) suggested that only a low to moderate proportion of the group is known, suggesting perhaps a total of around 1 500.

ABRS (2005a) reports 57 described species for Australia and an estimated 157 total, whereas DEH (in prep.) has figures of 56 described species out of a total of about 160.

World Described minimum World Described maximum World Accepted World Estimate Australia Described Australia Described % of World Described Australia Estimate Australia Endemic World Threatened83 Australia Threatened84 Australia Threatened % of World Threatened
~500 1 100 1 000 1 500 56 5.6% ~160 unknown 0 0
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Platyhelminthes (flat worms)

Estimates for the number of described species in the world are of around 20 000 (Hawksworth and Kalin-Arroyo 1995, Groombridge and Jenkins 2002, Brusca and Brusca 2003). Myers (2001g) reports 3 000 species of Turbellaria, 9 000 species of Trematoda and 5 000 species of Cestoda, while Ponder et al. (2002) provided a figure of 3 000–4 000 Monogenea which would give a total of 20 000–21 000 species. I have accepted the lower of these in line with the majority of reports.

I have found one estimate of the total number of species at over 80 000.

Estimates for the number of described Australian species vary from 1 506 (DEH in prep.) to 1 593 (ABRS 2005a) with estimates for total species of around 10 000 (DEH in prep.) and 10 806 (ABRS 2005a) although these estimates appear high (pers. comm. Alice Wells, ABRS June 2005). Endemism is likely to be low in parasitic forms in birds, marine fishes and in free-living marine forms and high in parasites of marsupials, reptiles and frogs, and in free-living freshwater forms (pers. comm. Alice Wells, ABRS, June 2005).

World Described minimum World Described maximum World Accepted World Estimate Australia Described Australia Described % of World Described Australia Estimate Australia Endemic World Threatened85 Australia Threatened86 Australia Threatened % of World Threatened
20 000 21 000 20 000 80 000+ 1 593 8.0% ~10 000 unknown 0 0
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Cnidaria (jellyfish, sea anenomes, and corals)

Estimates for the number of described species in the world vary from 9 000 (Groombridge and Jenkins 2002, Hickman et al. 2004), 10 000 (Groombridge and Jenkins 2002) to 10 000–11 000 (Brusca and Brusca 2003). I have accepted the figure of 9 000 as it is the figure most commonly cited in recent literature.

The number of described Australian species reported varies from 1 270 (ABRS 2005a) to 1 500 (DEH in prep.) with estimates of the total Australian fauna consistent at about 1 760 (ABRS 2005a, DEH in prep.). Recent information (pers. comm. Pam Beesley, ABRS, June 2005) indicated that there are probably around 1 043 species of Anthozoa, 51 species of Scyphozoa, nine of Cubozoa and perhaps around 600 species of Hydrozoa (Ponder et al. 2002), making a total of around 1 705 described species and around 2 200 species in total.

World Described minimum World Described maximum World Accepted World Estimate Australia Described Australia Described % of World Described Australia Estimate Australia Endemic World Threatened87 Australia Threatened88 Australia Threatened % of World Threatened
9 000 11 000 9 000 unknown 1 705 18.9% ~2 200 unknown 0 0
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Porifera (sponges)

Estimates for the number of described species of Porifera in the world vary from 5 500 (Myers 2001h, Brusca and Brusca 2003), 5 000–10 000 (Groombridge and Jenkins 2002), 6 000 (ABRS 2005b), 9 00089 to 10 00090. ABRS (2005b) also estimates that the figure of 6 000 described species is perhaps only about one-third of the total number of extant species.

Described species in Australia number 1 320–1 335 with about 56% endemic (Hooper and Wiedenmayer 1994). ABRS (2005a) and DEH (in prep.) estimate that there are 1 416 described species in Australia with the total number of species in Australian waters at about 3 500. Ponder et al. (2002) stated that about 45% of species on the Great Barrier Reef are endemic.

World Described minimum World Described maximum World Accepted World Estimate Australia Described Australia Described % of World Described Australia Estimate Australia Endemic World Threatened91 Australia Threatened92 Australia Threatened % of World Threatened
5 500 10 000 5 500 ~18 000 1 416 25.7% ~3 500 56% 0 0
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Other Invertebrates

A difficulty in listing this group is determining what belongs here, and what belongs in the Protoctista (see below).

Estimates for the number of described species in the various phyla in the world are given in the next Table and are compiled from Groombridge and Jenkins (2002), Brusca and Brusca (2003) and Hickman et al. (2004). Those for Australia are from ABRS (2005a) with the exception of the Entoprocta (Kamptozoa) and Sipuncula which are updated figures supplied by ABRS (pers. comm. Alice Wells, ABRS June 2005).

Tardigrade information was supplied by Sandra Claxton (pers. comm. Aug. 2005). She reported that an unpublished paper by her and Reinhardt Kristensen listed 46 marine species for Australia in 1998, and that her PhD (submitted in 2004) identified 182 terrestrial species of which 69 have been published in the literature. About 56% of the 182 species are endemic. She suggests that there are at least 500 species in total for Australia.

Most estimates for the world total of described species of Mesozoa are around 90, whereas ABRS (2005a) states that there are 100 described species for Australia. I have contacted several researchers around Australia, and all have the view that there is probably no-one in Australia who knows the number of described species in Australia. Similarly, the figure of 100 for the Loricifera reported by Groombridge and Jenkins (2002) does not fit with figures of around 10 reported by other researchers, or 22 supplied by Reinhardt Kristensen (pers. comm.93).

Other figures that differ from those given in the cited papers are 1 200 described species out of a worldwide total of 5 000–10 000 in Nermertea (Ponder et al. 2002).

Phylum Common name Hickman et al. Brusca and Brusca94 Groombridge and Jenkins World Accepted World Estimate Australia Described Australia Described % of World Described Australia Estimate Australia Endemic
Placozoa   1 1 1 1   0 0 0 0
Monoblastoza95   1 1  
Mesozoa mesozoans accepted? 9096 ~9097 90   100 110% 100  
Ctenophora comb jellies <100 100 ~100 100 150 10 10% 60  
Nemertea ribbon worms 650 900 ~900 900 5 000–10 000 81 9% 281  
Rotifera rotifers ~1 800 1 800 ~2 000 1 800   650 36% 1 300  
Gastrotricha gastrotrichs ~400 450 ~400 450   45 10% 45  
Kinorhyncha kynorhinchs 75 150 ~150 150   8 5% 8  
Nematomorpha horsehair worms 250 320 ~240 320   32 10% 32  
Entoprocta (Kamptozoa) kamptozoans 150 150 ~150 150 170 16 11% 16 87%98
Gnathostomulida gnathostomulids >80 80 ~80 80   8 10% 8  
Priapulida priapulans 18 16 17 18   2 12% 2  
Loricifera loriciferans few 10 ~10099 22100 >100 495 18% 6 50%
Cycliophora cycliophorans ?1 1 accepted? 1   0 0% 0  
Sipuncula peanut worms ~330 320 ~150 320   48 15% 48  
Echiura spoon worms 140 135 ~140 135   13 10% 13  
Tardigrada101 water bears 300–400 800 ~750 980102   112 (228) 11–23% ~500 56%
Phoronida phoronids ~10 20 16 20   6 30% 6  
Ectoprocta (Bryozoa) moss animals ~4 000 4 500 ~4 000 4 500 5 000+ 1 000 22% ~2 500 50%
Brachiopoda lamp shells ~325 335 ~350 335   58 17% 70  
Pentastomida tongue worms ~90 ~130103 accepted? 100   10 10% 10  
Chaetognatha104 arrow worms   100 ~70 100   10 10% 10  
TOTAL   8 800 10 409 ~9 700 10 573   2 213 20.9% 5 015  
Commonwealth of Australia