OLIGOCHAETA, NAIDIDAE OF THE WEST INDIES AND ADJACENT REGIONS

A very large collection of Naididae of the West Indies (153 localities), Suriname (15), Venezuela (2) and Florida (1) is studied. Five new species Nais barua, Dero scalariformis, D. tuna, Aulophorus kalina, A. barbatus are described. Dero magna, D. trifida, Aulophorus tridentatus, Allonais japonica, Pristina sima are redescribed. The 46 Naididae species of the West Indies are discussed by their taxonomy, distribution and habitat.


INTRODUCTION
In 1930 and from 1936 to 1973 Dr. P. Wagenaar Hummelinck (Utrecht) made a number of trips to study and to collect in different marine, limnetic and terrestrial biotopos of Surinam, Venezuela, the West Indies and Florida.The Oligochaeta collected in 1930 in the islands of Bonaire, Curaçao and Aruba were studied by Michaelsen (1933).One of us (G.Righi) was kindly allowed to study the material collected afterwards.The study of this collection resulted in four papers on the Oligochaeta families Tubificidae, Enchytraeidae, Glossoscolecidae, Ocnerodrilidae, Megascolecidae, Acanthodrilidae, Octochaetidae and Eudrilidae (Righi & Kanner, 1979;Medeiros & Neves, 1982;Righi & Hamoui, 1989;Righi, 1993).The much more numerous Naididae species are now presented.The region sampled by Hummelinck includes a little more than the Antillean (= Caribbean) Biogeographical Province belonging to the Caribbean Biogeographical Dominion which is the most septentrional region of the Neotropical Biogeographical Region (Cabrera & Willinck, 1973).The Neotropical Naididae are moderately known in Argentina (Di Persia, 1980a), Uruguay (Cordero, 1931a), Paraguay (Stephenson, 1931a), Lake Titicaca (Harman et al. 1988), Brazil (Righi, 1984) and Surinam (Harman, 1974).From the other regions there are only some short papers registered by Gavrilov (1981) and Harman (1982b).The first notice of Naididae in the Antillean Dominion is due to Stieren (1892) describing Dero multibranchiata from Trinidad.After this paper came those of Michaelsen (I.c.), Botea (1983) in Cuba and Dumnicka (1986) in some other West Indian Islands.These four papers reported a whole of 16 Naididae species, which is much below to the expected number in the so complex inner aquatic environment of the West Indies.So, our purposes are to supply the paucity of faunistic information, give an account of the variations of the species in the different biotopes and to understand their distribution in the West Indies.
We would like to express our deepest thanks to Dr. P. Wagenaar Hummelinck for his kindness giving us his Oligochaeta collection which made this study possible, and to Dr. John Milton (Universidade São Paulo) for English language corrections.

MATERIAL AND METHODS
Hummelinck's collection contains 4,975 Naididae specimens from 171 localities: 153 in 35 islands of the West Indies, 15 in Surinam, 2 in Venezuela and 1 in Florida (see below).To study the setae, every specimen was mounted in microscopical slides with glycerin-water (1:1).To study the inner anatomy, some worms of every species were dyed in toto with Mayer's paracarmin (Graupner, 1934) and studied in xylol and in the interface xylol-balsam.The specimens are preserved in permanent slides with balsam of Canada, 1-10 specimens per slide and they are deposited in the Department of Zoology, University of São Paulo (ZU), Brazil.

RESULTS AND DISCUSSION
Nais barua n. sp.

Bratislavia dadayi
Remarks: On confronting the descriptions of Naidium dadayi and Pristina unidentata we did not find any characteristic to separate them.On comparing our specimens with dadayi (= unidentata) we see they are differentiated by the teeth of the mid-body ventral setae; our specimens have a distal tooth which is considerably longer than the proximal one and dadayi has sub-equal teeth.We understand our animals are only a variation of dadayi because: 1) According to Michaelsen (1905a) in one specimen of dadayi the ventral setae of the last segments have their distal tooth distinctively shorter than the proximal one.2) In every ventral bundle of VI and VII of our animals, the most ventral setae have similar teeth and the most dorsal ones have distal tooth considerably shorter than the proximal one.

Haemonais waldvogeli
Remarks: On comparing the setal length registered in the literature to this cosmopolite species it is seen that the Gondwanian specimens have shorter setal length.The teeth of the needles are 2 times shorter than in European or North-American specimens.This, associated with the variability of the branchial fossa in preserved specimens, makes the identification of the species difficult.According to Botea (1983), the Cuban specimens have "finament serrées" hairs, but this is not showed in his fig. 10 and needs confirmation.Dero cooperi Stephenson (1932), D. bonairensis Michaelsen (1933) and; D. quadribranchiata Cernosvitov (1937) are distinguished from D. digitata only by their needles with teeth of equal length.
Remarks: The shape and measures of the setae in our worms agree with the South-American (Marcus, 1943;Harman, 1974;Di Persia, 1976) and European ones (Sperber, 1948;Hrabe, 1981).Perhaps due to contraction and preservation it was not possible to distinguish the dorsal lip and the marginal expansions of the branchial fossa, which are so characteristic of living animals.In the majority of our animals the stomach is restricted to segment VIII but occasionally it is in X; in Brazilian specimens (Marcus, 1943) it is in VIII-IX and in the European ones in IX, IX-X or X (Sperber, 1948).The division-zone of the Caribbean specimens is in XII-XIX, usually in XV or XVI; in Brazilian specimens it is in XVIII-XX and in European ones in XVIII-XIX.The great variability of these characteristics and discrepancies in the reproductive organs (Beddard, 1889;Chen, 1940;Marcus, 1944) makes us see Dero obtusa as an highly polymorphic species or, more probably, a complex of species indistinguishable by setal characteristics.Harman, 1974 (Fig. 1D-F) Dero (D.) magna Harman, 1974: 23, fig.4A-C.Material: Surinam 642,2 specimens (ZU-1315).Habitat: Limnetic; salinity 0.2%.Description: Length 6.9-16.5 mm.Diameter 385-424 µm.Number of segments 130. Division-zone lacking.Prostomium like an obtuse cone.Very contracted branchial fossa with dorsal opening and 2 or 3 pairs of short gills.Bundles of dorsal setae begining at V in one specimen and VI in the other; one hair and one needle setae per bundle.The hairs are straight, smooth, thin and 256-328 µm long.The needles (Fig. 1D) are 88-108 µm long; the nodulus separates the straight proximal 2/3 from the bowed distal 1/3.The apex presents the proximal and distal teeth of equal length, 4 µm, and the thickness or the proximal tooth is somewhat longer; there are 2-5 intermediate teeth.

Dero magna
The ventral bundles have 4, occasionally 3, setae in segments II-V, in the following segments there are 3 setae per bundle and 2 in the last segments.The length of the setae in II-V is 107-111 µm, the nodulus is medial and the teeth are alike in length, 10 µm, or the distal tooth is a little longer; the proximal tooth is the thickest (Fig. 1E).From VI onwards the length of the setae is 100-141 µm, the nodulus is proximal and the teeth have similar length or the proximal is a little longer.The proximal tooth is always the thickest (Fig. 1F).
Remarks: Dero magna is known only be the type specimen and the two worms described here, the three of them from Surinam.Dero magna and D. asiatica Cernosvitov (1930) are distinguished from the other species of the genus by the size of the setae and by the posterior setae of similar length or longer than the anterior ones.There is a great possibility that D. magna is just an aberrant form of Aulophorus pectinatus Stephenson, 1931a(= A. intermedia Loden & Harman, 1982).
Remarks: Dero heterobranchiata Michaelsem (1933) was described from a posterior fragment collected in Bonaire.Its probable synonymy with D. sawayai, as proposed by Sperber (1948), is due to a mis-translation of Marcus' (1943) text, the Portuguese word "duma" (= of one) was taken as "duas" (= two).So the two species are distinguished by the number of hair setae per bundle, 2 in heterobranchiata and one in sawayai.Loden, 1979 (Fig. 1G-J) Loden, 1979: 584, fig.1A-F Material: Aruba 98, 1 specimen.Surinam 120: 4 specimens (ZU-1317).Habitat Limnetic; salinity 0.03-0.1%.Distribution: North America (Loden, 1979).Neotropical Region: Aruba; Surinam (Righi & Hamoui).Description: Length: 3.7-3.8mm.Diameter 225-282 µm.Number of segments 35-37.Division-zone in XXI-XXII.Short semicircular prostomium.Branchial fossa (Fig. 1G) with a pair of slits in the posteriorlateral third and an hindmost wide gutter; a cross fold with the sphincter muscles lies between the fossa and gutter floors.Four pairs of gills are in the fossa; the first pair is dorsal, wide and flat, the other 3 pairs are ventral and fingerlike.All of the gills are contracted, in the side view they did not extend beyond the border of the fossa.A wide stomach with differentiated walls lies in IX followed by the intestine of similar diameter.There are a few chloragogenous cells from VII-VIII backwards.Thick commissural vessel are in VII-IX.Dorsal setae start from VI, 1 hair and 1 needle per bundle.The hairs are thin, bowed, smooth and 160-183 µm long.The needles (Fig. 1H) are 47-66 µm long, with a nodulus at the beginning of their bowed distal third.The apex has short teeth, 1-2 µm long, the distal tooth is a little longer than the proximal one; the shortest intermediate denticle departs from between the two main teeth.There are 4-5 ventral setae per bundle, generally 5.In II-V they are 113-120 µm long, the nodulus is medial or slightly distal, the teeth are alike in thickness but the distal tooth is 1.5 longer than the proximal one (Fig. 1I).

Dero trifida
Remarks: The species was only known in small populations in USA: Louisiana and North Carolina (Loden, 1979).Unlike our worms the North American specimens have the posterior ventral setae with distal tooth a little shorter than the proximal one.This difference is seen as an intra-specific variation without taxonomical value due to similarity of the other characteristics.
Remarks: The inner organization of our worms agree with the Indian ones (Naidu, 1962a).The shape and measures of the setae are similar too, but they differ in the posterior ventral setae, which in the Indian animals present the distal tooth slightly shorter than the proximal one.
Description: Length 1.5-2.5 mm.Diameter 165-172 µm.Number of segments 22-30.Division-zone in XV-XX.Prostomium short, semicircular.Eyes absent.Short branchial fossa with two pairs of somewhat flattened fingerlike gills (Fig. 1K).Bulky septal glands in V and VI.Wide thick walled stomach in VIII.Intestine begining at IX or X. Chloragogenous cells from VI backwards.Dorsal setae starting from VI, 1 hair and 1 needle per bundle.The hair setae present a thin aliform membrane at one side and smooth surfaces on the other sides; the width of the ala narrows making up two high stairs in the free border towards the apex.The view of the scalariform portion of the hairs depends upon the position of the setae (Fig. 1O).The needles are straight with a curve distal fourth; their apex is tricuspid (Fig. 1N), the proximal and distal teeth are alike in length and thickness and the medial tooth is thinner and a little shorter.The ventral setae are 3-5 per bundle in segments II-V, 3-4 from VI backwards, and 1-2 in the last segments.The setae of II-V have proximal nodulus and teeth of similar thickness but the distal tooth is almost 1.5 times longer than the proximal Remarks: Dero scalariformis has affinities with D. pectinata Aiyer (1929) in number of gills, number of setae per bundle and shape of the needle and ventral setae.They are distinguished by the hairs, which have one finely pilose side in pectinata or a thin smooth scalariform membrane in scalariformis.This introduces the questions of whether the hairs of the setae in pectinata are just cross thickenings of a thin alar membrane which is flat in scalariformis and whether the two of them are only varieties of a same species.

Dero tuna n. sp.
(Fig. 2A-D Eyes absent.Prostomium obtuse, wider than they are long.The very contracted branchial fossa leaves a small dorsal aperture making it difficult to see the gills, 2 or 3 pairs, contracted inside the fossa (Fig. 2A).Septal glands to V. Stomach in VII.Chloragogenous cells from VI backwards.Dorsal vessel displaced to the left; comissural vessels in V, VI-VIII.Dorsal setae from VI onwards, one hair and one needle setae per bundle.Hair setae straight, thin and smooth, length 122-130 µm.Needles 42-53 µm long, with straight proximal 2/3 and bowed distal 1/3, bicuspidate apex, distal tooth longer than the proximal, both of them are united by a thin membrane with convex margin and 10-12 longitudinal riblets (thicknings) in its distal half (Fig. 2B).Ventral bundles of II-V with 3-4 setae on each lessen to 1-2 in the last segments.The ventral setae of II-V are 72-79 one (Fig. 1L).The setae from VI onwards have distal nodulus and much shorter teeth than in anterior segments; the distal tooth is a little shorter and distinctively thinner than the proximal one (Fig. 1M).The length of the setae are in the Table 1.
µm long with proximal nodulus, thin teeth of similar thickness or the distal tooth is slightly thinner and always 1.5-2 times longer than the proximal (Fig. 2C).The relation between the lengths of the proximal: distal teeth varies from 7.8: 5.2-10.4:6.5 µm.The ventral setae of VI backwards are 50-64 µm long with medial nodulus and teeth of alike length, 2.6-3.9 µm, the proximal tooth is thicker (Fig. 2D).
Chloragocytes are presents from VI backwards.There is no differenced stomach.The dorsal vessel is dislodged to the left and commissural vessels are in VII and VIII.The dorsal setae begin at V, one hair and one needle per bundle.The hairs are smooth, straight and 113-148 µm long.The needles are 52-58 µm long; their proximal 2/3 are straight and the distal 1/3 slightly curved; the apex has two small teeth of similar length or the proximal is somewhat longer.A feeble intermediary denticle (Fig. 2F) is well seen in waterish or glycerinic preparations.The ventral setae are 4 per bundle to the mid-body region, 3 towards the back and 2 in the last segments.The length of the setae is 68-72 µm in II-V and 58-70 µm from VI onwards.The nodulus is medial.The distal tooth is nearly 1/3 longer than the proximal one in II (Fig. 2G); at the back the distal tooth shortens and the proximal lengthens gradually (Fig. 2H-J).The relations between the length of the distal: proximal teeth are in II = 10: 7, in VI = 10: 10 and in XII = 9: 11.
Remarks: Aulophorus kalina has affinities with A. indicus Naidu (1962) through the shape of the needles.The characteristics of A. indicus to distinguish from the new species are: 3 pairs of gills; ventral setae of II-V with distal tooth more than 2 times longer than the proximal one.The name of the new species is that of an old indian group from Venezuela and Caribbean Islands.Hrabe, 1966 (Fig. 2K-S)

Aulophorus tridentatus
Aulophorus tridentatus Hrabe, 1966: 380, figs. 24-28.Material: Margarita 10: 3 specimens (ZU-1321); 12: 4 specimens; 18: 9 specimens.Habitat: Linetic to weakly oligohaline; salinity 0.21-0.99%.Description: Length 4-5 mm.Diameter 174-257 µm.Number of segments 32-48.Eyes and division-zone missing.Prostomium conic, as long as wide.Wide branchial fossa (Fig. 2S) with 4 pairs of foliaceous gills and one pair of short parallel palps.The pharynx goes to IV. Septal glands are in IV-V.The thick walled stomach is dilated in IX-X.The intestine begin at XI. Chloragocytes are in VI backwards.The dorsal vessel is on the left and commissural vessels in VII-IX.The dorsal setae begin at V, one hair and one needle per bundle.The hairs are smooth and straight or a little curved.The needles present straight proximal 2/3 and a little curved distal 1/3; the short and divergent teeth have similar length or the proximal tooth is somewhat longer; there are 1-2 thin intermediate denticles difficult to see (Fig. 2K-L).The ventral setae are 3-4 per Remarks: Aulophorus tridentatus Hrabe (1966) was known only by one specimen from Ghana, Volta Lake at Kpandu (7.0°N-0.18°E).The African specimen differs from the Caribbean ones by its greater number of ventral setae.According to Hrabe the ventral setae of II-IV are 5-6 per bundle, 5 backwards and 4-1 in the last segments.We consider this difference without taxonomical value because there is concordance of other characteristics.

Aulophorus barbatus n. sp.
(Fig. 3A-D) Material: Surinam 120: 2 specimens (Holotype ZU-1322).Habitat: Limnetic; salinity 0.03%.Description: One specimen does not have the posterior end and the other one is regenerating the anterior end, the setae of II-V are missing; length 5.0 and 6.5 mm, diameter 360 and 437 µm, number of segments 37 and 38 respetively.The prostomium is triangular as long as it is wide.The dorsally opened oblonge branchial fossa has 3 or 4 pairs of retracted gills and one pair of diverging thin palps.The pharynx extends to IV, the three pairs of septal glands are in IV-VI.The esophagus passes gradually into the intestine, a stomach is missing.Chloragocytes begin at VII.The dorsal vessel is on the left and voluminous commissural vessels are in VIII-XII.The dorsal setae start from V, the regenerating specimens has one hair and one needle per bundle, the other has 1-3 hairs and 1-2 needles per bundle; when there are more than one hair per bundle one of them is longer and thicker.The hair setae are straight, 302-409 µm long, their apical 2/3-3/4 present a thick series of short threads on one side bundle to XI, 3 backwards and 2 in the last segments.The nodulus is submedial and the apex bicuspidate of thinner distal tooth; the distal tooth of II-IV, V is 1.3-1.5 longer than the proximal one (Fig. 2M-P); towards the back the teeth present similar length or the proximal one is slightly longer (Fig. 2Q-R).The length of the setae of one specimen of each locality are in Table 2. (Fig. 3A).The needles are 120-142 µm long, the nodulus is distal, the two main teeth are of similar length or the proximal one is somewhat longer, it is always thicker; there are 2-4 short and thin intermediate teeth (Fig. 3A).The ventral setae are 2-4 per bundle in II-V and 1-3 backwards.The setae of II-V are 124-130 µm long, 4 µm thick, their distal tooth is thinner and a little longer than the proximal one (Fig. 3B).From VI backwards the setae are 140-157 µm long, 5-6 µm thick, the distal tooth is thinner and of similar length or slightly shorter than the proximal (Fig. 3C-D).The nodulus is always distal.

Aulophorus huaronensis
Allonais japonica (Kondô, 1936) (Fig. 3E-G) Nais japonica Kondô, 1936: 385, pl. 23, fig.12. Material: St. Vincent 858: 1 specimen (ZU-1323).Habitat: Limnetic; salinity 0.05%.Description: Length 2,8 mm.Diameter 167 µm.Number of segments 24 plus a long posterior growing-zone.Eyes and division-zone are missing.Obtuse prostomium as long as wide.Septal gland to VI. Dorsal vessel dislodged to the left side; commissural vessels in VII-VIII.Dorsal setae from V backwards, one hair and one needle setae per bundle.The hairs are straight, smooth, 113-155 µm long.The needles (Fig. 3E) are 50-57 µm long, the proximal 2/3 are straight and the distal 1/3 is slightly curved; the bicuspidate apex has teeth of similar length, the proximal tooth is a little thicker.There are 4, occasionally 3 ventral setae per bundle diminishing to 2 and 1 in the last segments.These setae are alike one another throughout the body (Fig. 3F-G).The length of the setae is 50-58 µm in II-V and 52-61 µm from Vl backwards; the nodulus is medial to slightly distal; the distal tooth is 1.5 times longer than the proximal tooth, which is a little thicker.

Allonais inaequalis
Remarks: Four varieties (subspecies) of Nais paraguayensis were described: aequalis Stephenson (1920), barkudensis Stephenson (1921), ghanensis Hrabe (1966) and Dero (Aulophorus) paraguayensis aequatorialis Cernosvitov (1938b).The impropriety to put paraguayensis under Dero was demonstrated by Sperber (1948).The taxonomical value of aequalis, barkudensis and aequatorialis is seem sometimes at subspecific level (Stephenson, 1923;Marcus, 1943;Grimm, 1974), sometimes as single synonyms of paraguayensis (Sperber, 1948;Brinkhurst, 1971b;Harman et al. 1988).We consider aequalis, barkudensis and aequatorialis as independent species due to differences in the origin of the dorsal setae, shape of the needles and of the anterior ventral setae and because the circumtropical distribution of the typic form of paraguayensis makes difficult the subspecific isolation.According to Hrabe (1966) the distinction between Allonais paraguayensis ghanensis Hrabe (1966) and A. p. paraguayensis Michaelsen (1905) is based only on the degree of thickness of the atrophic distal tooth of the nedles.The great variability of this tooth, a characteristic of every atrophic structure, does not allow the specific distiction of ghanensis.
Remarks: The confusion between Pristina rosea and P. jenkinae began a little after jenkinae's description leading Marcus (1943) to consider jenkinae just as a form of rosea.The confusion was increased by re-interpreting jenkinae as a valid species (Sperber, 1948;Brinkhurst, 1971b) and descriptions of four "new species": idrensis, taita, nothofagi and sabanillica.The distinction among these "species" has been based on the relation between the lengths of the needle teeth.Kathman (1985) demonstrated that this relation presents a big inter-and intra-populational variability and also in the same specimen.In this way she put idrensis, taita and notophagi in the synonymy of jenkinae; but rosea was maintained as a valid species without any justification.Rodriguez (1986), studying Iberian specimens of rosea jenkinae and idrensis, considers valid species all of the three.However reorienting Rodriguez's figures we can see they exibit recoverings and gradual passage from one species to another, making the distinction impossible.We can confirm the variability in the length of the teeth in the needles and ventral setae of the same individual so that our material can be named rosea or jenkinae.Kathman (1985) and Dumnicka (1986) suggest the possibly synonymy of Pristina amphibiotica Lastockin (1927).However, the much greater angle between the needle teeth does not authorize this interpretation.P. sabanillica has no differences from P. rosea as it is now understand.
Remarks: Studying Naididae of the Brazilian Amazonia du Bois-Reymond Marcus (1947) described the same worm of P. americana having needles with equal and unequal teeth and smooth hairs, and specimens of P. neruviana Cernosvitov with hairs presenting two series of threads like in americana of our material and of Africa (Grimm, 1974).On comparing the original descriptions of P. americana Cernosvitov (1937), P. neruviana Cernosvitov (1939) and the variations observed in our material, a single distinctive characteristic remains to distinguish neruviana.It is the needle teeth of similar length and thickness and almost parallel to one another (an angle of 7°-8° is measured in Cernosvitov's 1939 figure) which is not sufficient to separate from our specimens from Nevis).The distinction between P. americana and P. synclites is based on the hairs (plumose in the first and smooth in the second) and in the posterior vascular loops (well seen in synclites and unrecognizable in americana).Righi & Hamoui (1989), studying specimens from Montserrat Island, have shown there are no differences between the asexual forms of P. longidentata and P. americana.The shape of the male sexual atrium is the only one difference between the sexual forms, and it was interpreted as a parthenogenetic consequence.However, these authors have maintained the two names to distinguish the two forms.P. orghidani Botea (1983) is seen as a junior synonymy of P. americana because they were set apart solely by the prostomial proboscis, which is well known to be a very variable characteristic to species of short proboscis (Marcus, 1943;Righi & Hamoui, 1989).

Pristina macrochaeta
Remarks: Pristina macrochaeta is in an isolated position inside the genus due to its aberrant cephalization, 2-3 segments, while there is only one segment to the other species.Harman (1974) suggestion there is a fall of anterior dorsal setae was not confirmed in our material.

ECOLOGICAL AND ZOOGEOGRAPHICAL CONSIDERATIONS
Hummelinck's collections is composed of Naididae from 171 localities, 153 in the West Indies, 15 in Suriname, 2 in Venezuela and 1 in Florida making a total of 4,975 individuals belonging to 33 species of 10 genera.The number of West Indian species was raised from 16 (Stieren, 1892;Michaelsen, 1933, Botea, 1983;Dumnicka, 1986) to 46 and the number of sampled islands are 43 now (Table 3).The more representative genera by species number in the West half of the genus occurrences in the West Indies and D. digitata and D. sawayai for the other half; the other species are confined to a small number of localities.Pristina is the more widely distributed genus in Africa (Grimm, 1987).In the West Indies it presents a slightly lower number of species than Dero does, but it is more widely distributed occupying 74.4% ofthe 43 sampled islands (Table 4).The Pristina species that covers a large number of islands is the P. americana followed by P. aequiseta.The occurrence percentages of the other species is much less but it varies more homogeneously than the Dero and Aulophorus species.The distribution of Aulophorus is a little smaller than that of Pristina; it has be found in 69.7% of the islands.A. furcatus accounts for almost all the Aulophorus' distribution; it is a complex polytypical species occurring in 67.4% of the islands.
Thirteen species (28.3%) -Nais barua, Dero bonairensis, D. delayi, D. heterobranchiata, D. haitiensis, D. scalariformis, Allodero delamarei, Aulophorus caraibicus, A. kalina, Pristina vinai, P. nunezi, P. cabacuensis and P. racovitzai are known only in the West Indies.D. bonairensis and D. scalariformis were found in two of the islands and the remaining species only in their type localities.Dero nectinata, Aulophorus hymanae and Allonais japonica are Asian imports and Aulophorus tridentatus came from Africa.Allonais nectinata and Pristina foreli are also imports but of dubious origin, probably Africa.The interpretation of Dero trifida, known in the center and the south of U.S.A., Surinam and Aruba, is discussible.As the greater number of Dero species live in warm regions and as the Microdrili are only little known in the tropical American areas it is more probable that D. trifida is neotropical.The other species are well known in the Neotropical Region.Slavina evelinae, Bratislavia dadayi, Dero sawayai, D. multibranchiata, D. evelinae, Aulophorus superterrenus, A. borellii, A. huaronensis, Pristina sima, P. americana and P. macrochaeta are typically South American species, some of them have a small penetration in other continents.Dero digitata, D. nivea, Aulophorus furcatus, Pristina rosea, P. aequiseta and P. longiseta are cosmopolite species.Haemonais waldvolgeli and Dero obtusa are probably cosmopolite too, but they are unknown in Australia.The other species have a wide distribution through the intertropical zone of the world.
Table 4 shows us that 4 species (8.7% of the 46 West Indian Naididae) live among saturated sand grains.Three of these species, Dero nivea, Aulophorus borellii and Pristina americana are hyporheic and Pristina racovitzai is interstitial in the seashore (Botea, 1983).P. americana was found in aquatic environment too and the same is waited to D. nivea and A. borellii due to their habits in other regions.The other 42 (91.3%)species are aquatic; 19 (41,3%) of them are exclusevely limnetic, which is the usual to the Naididae of other regions.Six species (13%) were found just in holygohaline waters; three of them, Dero pectinata, Pristina sima and P. foreli, are known from limnetic environment in   other regions.One species.Dero plumosa, was found only in polyhaline waters (salinity 23.66%) in Grenada.The other species present different degrees of adaptation to salinity: 11 species (23.9%) are limnetic to holigohaline, 3 species (6.5%) are limnetic to mesohaline and 2 species, Dero digitata and D. multibranchiata, have the greatest variations in salinity, they were found in limnetic to polyhaline environments.
As was demonstrated, the West Indian Naididae fauna is essentially Neotropical and of very wide distribution.The wide and discontinuous geoghraphical distribution of many Oligochaeta species can only be understood as a result of very ancient speciations, which would have resulted in animal groups spread over old continuous areas which were then fragmented (Bretscher, 1903;Michaelsen, 1911, du Bois-Reymond Marcus, 1947) and they would have had their distribution potentialized by the human agency.As the West Indian islands appeared after the division of the continents, only the human agency is able to explain their colonisation.Transport by animals (Benham, 1903) or by the wind (Timm, 1980) were never demonstrated, and they are not viable because the Naididae, like every other Oligochaeta, does not present any stage of resistance to loss of water neccessary to these kinds of transport.The endemism of 13 species (28.3%) may be explained by insufficent knowledge of the Neotropical Naididae.Nowadays knowledge of it is based on major studies in SE Brazil, Argentina, Uruguay, Paraguay, Lake Titicaca, Surinam and some smaller ones.A number of biotopes in Central America, the Guyana Plateau, Andean Cordilleras, W Amazonia and N Chaco still have unknown Naididae fauna.Moreover, the dominance of assexual archaeo or paratomical reproduction of the majority of Naididae species and the parthenogenesis of some (see under Pristina americana) are unfavorable for the neccessary mutations to give an origin to new species.However the West Indian internal aquatic environment is very complex.It is mainly composed of a small number of short water bodies, the majority are temporary and of variable salinity; brackish waters are predominant.This fact leads to a great adaptability as was demonstrated above and a strong mutational pressure which may explain the endemism of old-known holygohaline species such as Dero bonairensis, D. heterobranchiata and Aulophorus caraibicus.