Zoologicheskii zhurnal 1961. 41 (5) : 648 - 659
On the Morphology and Taxonomy of Polychaetes of the Family Chrysopetalidae E. Ehlers, 1864 (Genera Paleanotus L. Schmarda, 1861, Heteropale, H P Johnson, 1897, and Others)
S A Milejkovskij
Oceanological Institute Academy of Sciences SSSR (Moscow)1
The polychaetes of the family Chrysopetalidae Ehlers 1864 represented in the modern fauna of oceans of the world are from lesser number of genera poor in species (Hartman, 1959) and are insufficiently studied. The larval development of chrysopetalids is completely unstudied, albeit the knowledge of the morphology of larval and juvenile stages could bring light to the taxonomy of the family and to its relational ties to other groups of polychaetes.
Therefore, it seems to us, it deserves attention the description in this work of two of our recent findings: pelagical larvae of Chrysopetalidae, belonging to the species Paleanotus heteroseta O. Hartman 1945 and a new species of the mentioned family - Paleanotus schmardai S A Mileikovsky sp. n. The genus Paleanotus is for the first time encountered in the fauna of North-European seas.
Acknowledgements: I would like to express my sincere recognition of P V Ushakov and U Bao-Lin (Institute of Oceanology, Peoples Republic of China) for friendly concern about the work, advice, comments, big help in special literature of the taxonomy of polychaetes and for reviewing the work in manuscript, a also Ja A Birstein for worthy advice and comments on the contents and form of the work.
Pelagical larvae of Paleanotus heteroseta O. Hartman 1945
Material and localities
In the treatment of parts of the planktonic collection of the first route of the expedition vessel "Balaklava" accomplished in the summer of 1960 in the north-eastern Atlantic, G I Lukoj, in samples from two stations, situated in the waters of the Gulf Stream between the coasts of USA and the Bermudan Islands, we discovered very unusual pelagical larvae of a polychaete.
Our determination indicated, that they belonged to the species Paleanotus heteroseta O. Hartman 1945 and have never before been described. The co-ordinates of the stations 1) 37°ree;35' N 70°ree;43' W (August 12, 1960) 2) 35°ree;32' N 74°ree;25' W (August 16, 1960) (fig 3). On the first station were four specimens found - 3 in the layer 25 - 0 m and 1 in the layer 100-50 m. All these had four parapodial segments. On the second station in the layer 100-0 m was one specimen found with five parapodial segments. The taxonomical affiliation of the larvae were determined by the construction of parapodia and the outer morphology.
Description. Parapodia bear densely packed (crammed) fan-shaped spatula-shaped dorsal setae, having a characteristic golden-brown colour, longitudinal and transverse patterns and covering almost all of the dorsal surface of the worm (fig. 1 A-¸); such setae are only present in polychaetes of the family Chrysopetalidae ( Fauvel, 1923, 1927; Ushakov, 1955; Ehlers, 1864-1868). The affiliation of the larvae to the genus Paleanotus Schmarda, 1861 was determined by the presence of two types of dorsal setae: very wide spatula-shaped (fig. 1 G-¸) and narrow/thin tapering at the end (fig. 1 E), simultaneously present which characterize only this genus and including in its components the majority of the systematics of Heteropale H. P. Johnson, 1897 (Schmarda, 1861: Johnson, 1897; Gravier, 1900; Augener, 1913; Hartman, 1945; Ushakov, 1955 and others). But in Heteropale there are on the larger dorsal setae - "paleae" - additional structures (see below), being absent in Paleanotus. In the given larva these additional structures are absent. Moreover their setae, both the dorsal (paleae), and the ventral (fig. 1 G-Z), are very much the same as those in adult Paleanotus heteroseta Hartman, 1945 - the only species of the given genus, recorded from the Atlantic coast of America and found only in this part of the coast, close to the place of our recording - at the coast of North Carolina (Hartman, 1945). Considering all the above-mentioned, we assign the found larvae to precisely this species.
The larvae of P. heteroseta have a characteristic structure (fig. 1 A-V). The body of the larva consist of a large cephalic part, four-five parapodial body segments and a pygidium. The cephalic part, as in many other polychaete larvae (Sveschnikov, 1959) includes the foundation of a prostomium and a peristomium, a division of muscular rolls, bearing a annular prototrocha (fig. 1 A-B) with comparatively short cilia. Three pairs of bright-red eyes are found (fig. 1 V) on the prostomium. Two of these are situated on the frontal, upper part of the side of the head, but the other - on the lower. The latter pair of eyes, are frontally situated, quite large. We found three pairs of eyes in the largest larvae (fig 1 V), in the smallest (fig. 1 A-B) the third pair of eyes were not discovered, possibly because of their small size and weak pigmentation.
As is well known, the adult polychaetes of the genus Paleanotus have two pairs of eyes (Ushakov, 1955 and others). Obviously, one pair of eyes, implanted in the larvae, are later in adult individuals reduced, as is typical, for instance, for many Polynoidae and Sigalionidae.
The peristomium bear two pairs of tentacular cirri (fig. 1 A-V), obviously, dismounted from the larvae before metamorphosis. The peristomium is, presumably, merged with one of the body segments, as it bears some large ventral setae (fig. 1 A, B). The tentacular cirri are situated on a vertical line, the upper one is longer (fig. 1 A-V). The parapodia of the first body segment bear two tentacular cirri (ventral and dorsal), such as the peristomium and the first segment bear all together four pairs of tentacular cirri (fig. 1 A-V). The parapodia are completely developed and possess a full set of setae, but also dorsal and ventral cirri. They have two types of dorsal palea and two types of ventral setae (fig. 1 G-Z). Every parapodium hold on the notopodial ramus no less than 10 spatula-shaped palea, situated as a fan (fig. 1 B). The setae, situated on different places on the fan, differs somewhat one from the other in form and structure.
Fig. 1. Morphology of pelagical larvae of Paleanotus heteroseta Hartman, 1945,
A, B - external view of two larva, having four parapodial segments (from above and the side); V - external view of larva with five parapodial segments; G - palea from the larva with five parapodial segments in fig V; D-E - different types of paleae from the second left parapodium of the same larva (E1 - subacicular thin palea); u one of the larger palea of the larva in figure A; Z - ventral seta of the larva in figure V; I - larval peristomial seta from the larva in figure A.
Both their two sides are toothed, bear longitudinal crests and have transverse striation (fig. 1 G-¸), however the number of crests differ in different setae.
On the 'fan' are palea, more or less widening at the distal part; the first - rather spoon-shaped, the other - typical spatula-shaped (fig. 1 G, D, E, ¸). In addition, between them are a complete row of transitions. The widest palea bear 17-18 longitudinal crests, the narrowest - 10, the intermediate in width - 16, 14, 12 (fig. 1 G-E, ¸). According to Hartman (1945, pl.1, fig. 1) in adult P. heteroseta spatula-shaped palea are toothed only on one edge. It seems to us, that she was mistaken. As is seen in our fig. 1 D, the edge of the palea have a tendency to fold such that the seta eventually attain a shape all more rounded furrow. Therefore the edge of the setae do not appear from the side, but/or from above, and the bottom lies under the middle parts of the setae toothing of one of the edges (or even both) can quite easily not be noted.
The second type of dorsal setae - thin pointed at the tip - yet have only started to be implanted: on every parapodium on more adult larvae (fig. 1 V) there are only one of these setae fig. 1 E1. They have a form of two-side-toothed daggers, situated in the vicinity of the aciculae (fig. 1 E).
All the ventral setae (fig. 1 Z) are compound heterogomph, consists of a long shaft and a short terminating part, toothed on the inner of the concave side.
Hartman (1945) determined three types of ventral setae in adult P. heteroseta: 1) spinigerous, 2) falcigerous with a long terminal segment, 3) falcigerous with a short terminal segment.
As is seen in fig. 1 Z, in largest of our larvae have both types of falcigerous setae, characteristic, in accordance with Hartman, for adult forms of this species. A few spinigerous setae, presumably, are found in later ages.
The shaft of the ventral seta have transverse striation. All setae, including all larval stages are of a golden-yellow colour. The pygidium is comparatively small, it bears a pair of short anal cirri. Telotrocha is not present. The colour of the body of the larva is yellowish, on the cephalic region is an accumulation of brown pigment.
Similarity and difference with the other polychaete larvae.
A comparison of our recent studies (Milejkovskij, 1960, 1961) of larvae of some Amphinomorpha (genera Amphinome, Chloenea and Euphrysone) with larvae P. heteroseta shows, that between them there is nothing in common. It seems to us therefore, that the given group of polychaetes do not constitute close related genera, as this appeared in the old systematics (Quatrefages, 1865; Baird, 1870 and others). The description of these larvae by form and the position of eyes resemble partly to larvae of Sigalioninae and to a lesser extent to larvae of Polynoidae (Sveschnikov, 1959; Rasmussen, 1956 and others). It is interesting to note that similar large toothed on two sides larval setae on the peristomium is absent from other larva of polychaeta errantia, except Chrysopetalidae, these are also present in larvae of Sabellariidae (Wilson, 1929; Dales, 1952) and on the first body segment in larvae of some Spionidae (Hannerz, 1956).
These separate similarity features of larvae P. heteroseta with larvae of sedentary polychaetes might be explanations or convergences due to similar way of living of pelagical larvae (the presence of large larval setae lighten the larvae which "float" in the water masses) or the presence a particular remote relative ancestry between the chrysopetalids and the sedentary polychaetes, or, possibly, both at the same time.
The larvae of P. heteroseta were found in open sea at great depth (>1000m) and far from the coast (more than 100 miles), while, according to Hartman (1945), the position were this species as an adult is found on the coast of North Carolina is on the shore not sub-littoral depth. Obviously, the numerous palea and larval setae form such great "parachutish surface" that these larvae, might be carried away by a coastal current to the Gulf Stream, which could transfer them great distances.
Paleanotus schmardai S. A. Mileikovsky, 1961 sp. n..
Material and localities. One quite young specimen, was caught with a plankton-net Jedi, which got stuck in the bottom at 310 m. The co-ordinates of the station - 71°12' N and 24°14' E (expedition with the vessel "Tunets", route 8, station 15, 17 July 1959). A chrysopetalid which has never before been registered was found by the coast of north-eastern Norway, only 30 miles east of the border between the Norwegian and the Barents Seas along the line Nordkap-Medveschij. In the net entered, obviously, the whole worm, but, unfortunately, in the state of two divided parts; the frontal part, constitutes of the head and nine body segments, and the terminal part of the pygidium and eight body segments. Such that by the fracture of the polychaete parts of the middle body-segments could be missing, symmetrical considerations indicate that the polychaete had from 17 to 20 body-segments. The station was taken quite close (ca 10 miles) from the shore, such that P. schmardai could be removed to these depths from coastal shallow waters.
Description. The worm have a quite characteristic external appearance. The cephalic region is very small, the form is almost hemisphaerical. On the dorsal surface of the cephalic region, occupying more than their place, are four large bright-red eyes situated, forming a trapezium (fig. 2 A). Between the eyes is a unpaired cephalic tentacle; it is spool-shaped, and has almost the same length, as the whole cephalic region. The cephalic region, protrude comparatively little on the dorsal side, and besides it is covered, like a summerhouse, by the crossing of the dorsal setae from the parapodia of the first segment. Symmetrically situated on the ventral side of the cephalic region (fig. 2 B) are two slightly smaller, than the upper, cephalic tentacles and two massive cylindrical palps. On the side of the cephalic region are the basis of two pairs of tentacular cirri (fig. 2 B, V) situated. The cirri themselves, unfortunately, were lost before catching of the worm. The basis of the tentacular cirri (on one of which remain preserved the cirri itself - fig. 2 V) were situated between the cephalic region and the neuropodial rami of the parapodia of the first segment and is visible only from the ventral side. Accordingly, the whole cephalic part bear nine appendages: three tentacles, two palps and two pairs of tentacular cirri.
The muscular proboscis is armed with bright-yellow chitinous teeth (fig. 2 B). A wide bundle of dorsal setae covers almost the whole of the dorsal surface of the worm. As in representatives of the genus Chrysopetalum (Ushakov, 1955), the parapodia of the two frontal segments (the dorsal setae which in P. schmardai are narrower, than setae of the following segments) are directed forward and found on one same level as the cephalic region. Long dorsal cirri are found under the bundles of dorsal setae, as in Chrysopetalum, (fig. 2 A, G).
The parapodia are, as in other Chrysopetalidae, biramous (fig. 2 G, D). From the notopodial rami of the parapodium go two bundles of dorsal setae. The subacicular bundle consists of densely packed spatula-shaped setae. These setae are situated in two rows. The lower row, supplemented to the surface of the body, consists of longer setae, the upper - of shorter. Obviously, the setae of the upper row are formed later. The number of setae of each and every one of the rows are equal to 8-12, usually on the lower row there are slightly more.
Fig. 2. Morphology of Paleanotus schmardai Mileikovsky, 1961, sp. n.
A - external view of the former half of the worm (view from above); B - cephalic region of the polychaete (view from below); V - scheme for the location of tentacular cirri of the first segment (view from below); G, D - structure of typical parapodium from the middle part of the body of the polychaete; E - large spatula-shaped palea (E1 - palea from the upper row, E2 - from the lower row, E3 - scheme of a transverse cut through E2); Z1-Z2 - thin subacicular palea, u distal end of wide spatula-shaped palea from the lower row (Z and u - in the same scale, the difference in nature of the toothing is easily seen ); I - ventral spinigerous seta.
All the spatula-shaped setae are toothed on both sides (fig. 2 E, ¸) and have a structure with longitudinal ribs and transverse striation. In addition the transverse striation is expressed clearer than the longitudinal, however in other representatives of this genus, together with the genus Chrysopetalum E. Ehlers, judging from the literature, it is the other way round - the longitudinal striation is clearer (Ehlers, 1861; Fauvel, 1923; Hartman, 1945; Rioja, 1947; Ushakov, 1955 and others).
On the large spatula-shaped setae on the lower row the number of longitudinal rows equals 35-40. This is considerably more, than in other species of the genus: in P. heteroseta there are 17-18 of them (Hartman, 1945), in P. purpurea - just as many (Rioja, 1947), in P. chrysolepis from South Africa - 11 (Schmarda, 1961). The edge of many setae are slightly bent upwards, such that they by form look like shallow furrows. The convex side of the seta forms a keel, such that a transverse section across the seta looks like a transverse cut across a leaf of aloë (fig. 2 Z2 ). The keels turn to the surface of the body, from a view from above they are transparent through the mass ot the seta and looks like a dusky line (fig. 2 E2). The subacicular bundle consist of thin, terminally tapering two-side-toothed seta (fig. 2 G, D, Z). The number of them in a bundle is about 7-11. As is seen from a comparison of the figures E, ¸ and Z from fig. 2, as from the shape, as from the character of the toothed setae from both bundles differ from each other and between them are no transitional shape.
From the neuropodial ramus of the parapodia leave compound heterogomphous ventral setae (fig. 2 G, D). The number of setae in a bundle are of the order 15-20. All the ventral setae are spinigerous, with a long, resembling in shape a sabre, terminal segment (fig. 2 I). Falcigerous seta are absent from all the parapodia, they did not appear on any of the 17 segments. Of the other species of the genus P. chrysolepis have only falcigerous setae (according to Hartman, 1945), but in P. heteroseta and in P. purpurea - there are both falcigerous and spinigerous (Hartman, 1945; Rioja, 1947). From the parapodia extend long dorsal and short ventral cirri. The pygidium is small, without anal cirri (possibly, they were lost before the catching). The colour of the body of the worm was yellow. The setae are golden. The whole length of the worm was ca. 3 mm. The number of segments, as already stated, from 17 to 20.
Review of the systematics of the family Chrysopetalidae E. Ehlers, 1864 and the genera Paleanotus L. Schmarda, 1864 and Heteropale H. P. Johnson, 1897
In the recent work of Hartman (1959) and P. V Ushakov (1955) this family is divided in four genera: 1) Bhawania L. Schmarda, 1961; 2) Chrysopetalum E. Ehlers, 1964; 3) Dysponetus G. Levinsen, 1897; 4) Paleanotus L. Schmarda, 1861. Our material, but also the one given by Jorge (1953), say about this, that it is necessary to add to the characteristic independent genera the genus Heteropale H. P. Johnson, 1897, earlier made synonymous with the genus Paleanotus. The introductions of tables for the determination of chrysopetalids to genus by Gravier (1900), Ushakov (1955) and Hartman (1945) can not be called successful, since for them the genus Heteropale is not considered and, besides, used impermanent adult characters, for instance, number of eyes and number of body segments. For example, from Gravier and Ushakov, there are only in Bhawania more than 60 segments, but in the remaining genera up to 60. However Rioja (1947) established that in P. purpurea the body consisted of 120-130 segments. Ushakov (1955) stated the in the genus Dysponetus there are no eyes. According to Hartman (1959) and N. P Annenkova (1935), Dysponetus pygmaeus Levinsen and Taphus hebes Webster et Benedict are the same form. However in T. hebes there are one pair of very small eyes (Annenkova, 1935, p. 235). Moreover, speaking of the presence of four-eyed adults, it is stated that Paleanotus have six eyes in the stage as a pelagical larva. Therefore we present a new key (see below) for the determination of chrysopetalids to genera, in which is used characteristics of general systematical characters of the peculiarities of the construction of the cephalic end and palea of different genera, put up on the basis of Jorge (1953) and partly our work, and considering the genus Heteropale Johnson, 1897; besides also using some characters from the determination-tables of Ushakov (1955)
Key for the determination of genera of Chrysopetalidae mainly on the construction of the cephalic end and on dorsal palea
1 (2) On parapodia is only one type of dorsal setae / paleae.....................................3
2 (1) On parapodia are two types of paleae: broad spatula-shaped and smaller in size, narrow, toothed at the end............................................................................7
3 (4) Dorsal setae thin, toothed on one side, more similar to setae of Polynoinae. In adults of the given form are 1 pair of small eyes which are often absent. On segment 1 are two pairs of tentacular cirri, one of which looks like a peristomial papilla. Small forms (12-15 segments) .................................................................................Dysponetus G. Levinsen, 1879
4 (3) Dorsal setae of other shape. In adult individuals are two pairs of big red eyes..............................................................................................................................5
5 (6) The first segment of the body carries on pair of tentacular cirri (the two following segments three pairs). Palea wide or thin, typically with the same width on all its extent, two or one side toothed. Toothing is blunt and with light contours. The distal end of the palea is rounded. Palea form dense transverse rows and covers all the dorsal side of the worm........................................................................Bhawania L. Schmarda, 1861
6 (5) The first segment of the body carries two pairs of tentacular cirri (the two following segments four pairs). Palea notably widened at the distal end, of spatula-shaped form. The distal end of the palea is pointed. with teeth on both sides - toothing is dense and sharp.......Chrysopetalum E. Ehlers, 1864
7 (8) The first segment carries on pair of tentacular cirri (the two following segments three pairs). The larger palea are asymmetrical - lanceolate, sharp ended and bent on one side. Toothing only on the convex side. The end of the palea sharpened and appear prolonged on its bent side. On the larger palea are 15-16 longitudinal ribs, from which every second ornament-structure of small rounded plates ................................................................................Heteropale H. P. Johnson, 1897
8 (7) The first segment of the body carries two pairs of tentacular cirri (the two following segments four pairs). The larger palea are symmetrical in structure, spatula-shaped form and toothing on both sides. On their longitudinal ribs are no additional structures of round plates . ..................................................................................Paleanotus L. Schmarda, 1861
Whitin the given family is a most confused system for the genus Paleanotus. For the first time the genus was established by Schmarda (1861) for a palmyrid from the region of Cape Town - Paleanotus chrysolepis L. Schmarda, 1861, gen. et sp. n., was characterized by two types of paleae, seven appendages of the cephalic region (of which four - are two pairs of tentacular cirri on segment 1), and, judging from Schmarda's painting, only one long falcigerous setae (according to Hartman (1945) and our work).
Later Johnson (1897) discovered in the north-eastern Pacific yet another genus of chrysopetalids with two types of paleae and seven appendages on the cephalic region - Heteropale bellis H. Johnson, 1897 gen et sp. n., differing, however, from P. chrysolepis, by the presence of only one (only dorsal) pair of tentacular cirri on the first segment, the segmentation of parapodial cirri, asymmetrical palea with 16 longitudinal ribs, every second of which have sculptures of small round plates, but also by the presence of two types of falcigerous ventral setae (Johnson, 1897, pl. VI, fig. 23).
Shortly afterwards Augener (1913), found in the south-western waters of Australia a chrysopetalid with two types of palea, assigning it to the species P. chrysolepis L. Schmarda and submitted the diagnosis of both Schmarda and Johnson to revision. The result of which was that the form found by him had the same two types of palea, as both P. chrysolepis and H. bellis, while nine (three cephalic antenna, two palps, and two pairs of tentacular cirri), and not seven cephalic appendages, Augener decided, that both Schmarda and Johnson were misstaken.
According to Augener, Schmarda registered all the antennae and cirri, but not the palps, while Johnson either did not notice the second pair of tentacular cirri or dealt with an injured specimen. In addition, Augener stated that Paleanotus and Heteropale had paleae of one construction and that on larger paleae were ca. 16 longitudinal ribs, of which (every second) had ornamental structures of round small protuberances. He therefore considered, that P. chrysolepis and H. bellis - beyond any doubt were the same form, i.e. one species - P. chrysolepis L. Schmarda. Unfortunately, Augener gave very short descriptions of his own specimens and did not supply any figures.
After Augener the determination of Johnson were accepted as being wrong, and the designation Heteropale bellis Johnson, 1897 was made synonymous to P. chrysolepis Schmarda, 1861. Since then the form, described by Johnson, obviously, has several times been found along the coast of the Pacific, in Alaska, Canada, USA, Mexico, Central America and northern end of South America right up to Peru (Hartman, 1939, 19040, 1948,1959, 1961; Hartman and Reish, 1950; Monro, 1933; E. Berkeley and C. Berkeley, 1941, 1948). None of the mentioned authors made a sketch especially for their specimen, but Berkeley brought to their large compilation (1948) the painting of Johnson (1897).
All these authors related their findings to P. chrysolepis Schmarda, but Hartman also used the denomination Paleanotus bellis Johnson as a synonym to P. chrysolepis (1959) or as an independent species denomination (1961).
In the 40ies were two new species of Paleanotus found. Hartman (1945) described P. heteroseta sp. n. from the Atlantic coast of USA in the region of North Carolina, Rioja (1947) - P. purpurea sp. n. from the south-eastern shores of California.the author did not especially study the structure of the end of the cephalic region, the fundamental characters of the parapodial structure are given to us below.
In recent years Day (1957, 1960) show on findings of P. chrysolepis Schmarda from different parts of south-western Africa, but in none of his works is a picture present, nor a description. Ushakov and Bao-Lin (1960) observed P. chrysolepis in the Yellow Sea. Due to the noble kindness of Ushakov we were given the possibility to be familiar with preparations of parapodia, which were examined. The specimen from the Yellow Sea is completely identical with H. bellis Johnson from northern Pacific in structure (presence of small plates on the ribs) and form of the paleae and notably different from all species of Paleanotus Schmarda sensu stricto.
Quite recently Jorge (1953) specially studied the morphology of the cephalic region of Chrysopetalum sp., Bhawania sp. and Heteropale sp. from the coastal waters of Portugal and established, that in Chrysopetalum sp. on the first segment there are both dorsal and ventral tentacular cirri, but in Bhawania sp. and Heteropale sp. - only dorsal, but ventral were absent, i.e. Chrysopetalum sp. have two pairs of tentacular cirri on the first segment, whereas Bhawania sp. and Heteropale sp. only have one. Jorge therefore argued that, Johnson was right, dividing Heteropale bellis into a special genus, but Augener, making it synonymous with P. chrysolepis, was mistaken. Jorge himself resolutely divided Paleanotus and Heteropale, counting them as two independent genera. As showed by us above, in larvae of P. heteroseta and in adult P. schmardai sp. n. there are two pairs of tentacular cirri on the first segment. Accordingly the genus Paleanotus Schmarda and the genus Chrysopetalum, are characterized by the presence of two pairs of tentacular cirri, and not one as the genus Heteropale. Therefore we support on every point of Jorge's opinion about the independence and the non-identity of these two genera, but about this we will talk longer about in the following. Jorge gave in his work (1953, fig. 10) a scheme, in which it shows, that the ventral cirri of the second segment are displaced under the dorsal cirri of the first segment in Bhawania and Heteropale, which gives the impression that on the first segment there are both dorsal and ventral cirri, but on the second - only dorsal. To find out about this, it was necessary with special morphological investigations. Augener was not a former morphologist and had small-sized specimens, may have been completely confused and assumed that ventral cirri of the second pair were cirri of the first pair. While it actually might have had the form with nine appendages. It seems to us, that it is most likely with him was Heteropale sp., as he speaks of the ornamentation on the palea of his specimens and writes of a couple of identities of his specimens with Johnson's (by the way, Johnson's pictures and description is better than Schmarda's). Nevertheless it is impossible to exclude the possibility, that Augener dealt with a Paleanotus sp. In any case his specimens did not belong to P. chrysolepis, nor to H. bellis.
Unfortunately, Jorge did not bring a painting of the setae of his species in his work, and without this, it seem to us, one cannot identify thouroughly neither the systematics of the given two close genera, nor in the system of the whole the family.
As is seen from our description of the structure of pelagical larva of P. heteroseta, the whole set of characters, which characterize their generic and specific affiliation are present already in the larva. In larvae of P. heteroseta there are two pairs of tentacular cirri on the cephalic region. While on it on the parapodia of the first segment there are both dorsal and ventral cirri. Consequently, here actually first dorsal cirri coincide with the first ventral (as in Chrysopetalum in the work of Jorge), but do not arise from the translocation of the second ventral under the first dorsal, as it was established by Jorge for Heteropale and Bhawania. On the largest paleae of the larvae there are 17-18 longitudinal ribs, as in adult P. heteroseta, and there are on the limits of measurement two to three types of ventral setae.
All this says that the difference in head structure and parapodia which is observed between different species of the genus Paleanotus Schmarda, and also between them and Heteropale bellis Johnson, and between them and other genera of chrysopetalids, is not an artefact or a result of an injury, but constitute an expression for real generic differences, that are founded in them in at the stage of pelagical larvae.
On the basis of everything said above we give a key for the determination of polychaetes of the two afore-mentioned genera to species, constructed by the same principle, as the key for the determination of all chrysopetalids to genus (se above).
Key for the determination of species of Paleanotus and Heteropale (not considering Heteropale sp. Jorge and Heteropale? sp. Augener)
1 (2) Larger paleae asymmetrical, lanceolate, with a sharp tip and bent on one side. Toothing only on the convex side. On every second of their
longitudinal ribs there are a structure that looks like small round platelets. Two types of falcigerous ventral setae. On segment 1 there is one pair of tentacular cirri (three pairs on the two following segments) ..............................................................................Heteropale bellis Johnson, 1897
2 (1) Larger paleae symmetrical in structure. Toothing on both sides. On the longitudinal ribs there are no structure with rounded platelets. One or three types of ventral setae. On segment 1 there are two pairs of tentacular cirri (4 pairs on the two following segments)..........Paleanotus sensu stricto
3 (6) Three types of ventral setae - spinigerous and long and short falcigerous. Large palea with 17-18 longitudinal ribs.
4 (5) Parapodia with 18-20 large paleae. Long form, having from 120-130 body segments............................................................................P. purpurea Rioja, 1947
5 (4) Parapodia with 9-10 large paleae. Short forms.
....................................................................................P. heteroseta, Hartman, 1945
6 (3) Having barely one type of ventral setae. The number of longitudinal ribs on the larger paleae not equal to 17-18.
7 (8) Only long falcigerous setae. Paleae with 11 longitudinal ribs
.........................................................................................P. chrysolepis, Schmarda.
8 (7) Only spinigerous setae. Paleae with 35-40 weakly expressed ribs
....................................................................................................P. schmardai, sp. n.
Finally one should draw attention to, that the majority of systematicists, obviously, did not treat long enough attention to the fine structure of the paleae of chrysopetalids, or possibly, also simply ignored them. For instance, Hartman (1945) and Rioja (1947) bring in the descriptions the number of ribs present on the paleae of the species Paleanotus heteroseta and P. purpurea. About this one might barely judge from their paintings, which might have been schematic. It seems to us, that for the further studies of the species of the given family, or most of all at the description of new species or revision of old, one should treat more attention on these characters,such as the structure of paleae and type of ventral setae of them, the proportions of latter, but also on the structure of the cephalic end and their appendages.
Geographical distribution of polychaetes of the genera Paleanotus and Heteropale
The map (fig. 3) is a compilation by us on the material of all presented works above, bringing together all the known findings of these two genera, Paleanotus chrysolepis, P. heteroseta, P. purpurea, Heteropale bellis, Heteropale sp. Jorge and Heteropale? sp. Augener - all were found on either the littoral or on the upper levels of the sublittoral. P. schmardai, it is true, were found by us on the depth of 310 m., but at such closeness to the shore, that its occurrence on this depth simply all in all is explained with the disposition to drift of their larvae from the neighbourhood of shallow coastal waters. Therefore the whole group is characterized by location in shallow coastal waters. Before the analysis of its distribution we inevitably must arrive at the conclusion, that it by no means is by coincidence, but reflects generical relations between the groups.
Fig. 3 Geographical distribution of polychaetes of the genera Paleanotus Schmarda, 1861 and Heteropale, Johnson, 1897
1- Paleanotus chrysolepis Schmarda, 1861 (by Schmarda, 1861, Day, 1957,1960); 2-Paleanotus heteroseta Hartman, 1945 (herself); 3- pelagical larvae of P. heteroseta (our work); 4- P. purpurea Rioja (himself, 1947); 5- P. schmardai sp. n. (our work); 6- Heteropale bellis Johnson, 1897 (hmslf, Hartman, 1939, 1940, 1948, 1959; Hartman and Reish, 1950; Monro, 1933; Berkeley, 1941,1948); 7-Heteropale (?) sp (=P. chrysolepis Augener, 1913, non-Schmarda, 1861) (hmslf); 8- Heteropale sp. (Jorge, 1953); 9- Heteropale bellis Johnson (=P. chrysolepis Ushakov et Bao-Lin, 1960 (non-Schmarda, 1861)) (thmslvs).
The species of the genus Paleanotus have a limited distribution, excluding P. purpurea Rioja, all are located in the Atlantic and, moreover, as is seen in fig 3, four species of the genus form two clear pairs.
The first pair - P. heteroseta Hartman and P. purpurea Rioja are situated in a amphiamerican way somewhat to the north of the northern tropic. The second pair - P. chrysolepis Schmarda and P. schmardai sp. n. are located to the southern and northern end of the eastern Atlantic and are situated strictly bipolarly to each other. P. heteroseta and P. purpurea are morphologically very close: they have similar paleae and the same set of ventral setae. In turn, P. chrysolepis and P. schmardai are closer to each other (common characters - presence of only one, not three as in the American species, type of ventral setae), than to the American species. Such that all of the map in its whole, obviously, reflects generical ties of the species within the genus.
The species Heteropale bellis Johnson,1897 occur along all of the western coast of America from Alaska to Peru, consequently, it has in the eastern Pacific a wide complete area. It also occurs in the western Pacific - in the Yellow Sea (in the region of Chindao). Considering the catch of Heteropale sp. in Portugal, in the work by Jorge (1953), the distribution of the genus as a whole might be characterized as principally amphiboreal, or if, one consider Heteropale? sp. Augener, also bipolar.
(N. B. The references below are translated from Russian without checking any previous attempts, and shall accordingly be treated as tentative).
Annenkova, H P, 1935 Some words about Dysponetus pygmaeus Levinsen and Euzonus arcticus Grube (Annelida, Polychaeta). Dokl. AN SSSR, 3 (8), 5 (65), 233-236
Milejkovsky, S A, 1960. On the belonging of polychaete larvae of growing type from the plankton of the Norwegian and Barents Seas to the species Euphrosyne borealis Oersted, 1843 and all of the given tyypes of larva in the families Euphrosinidae and Amphinomidae (Polychaeta Errantia, Amphinomorpha). Dokl. AN SSSR, 134, 3, 731-734 - 1961
- On the belonging of two polychaete larvae of growing type from the plankton of north-eastern Atlantic to the species Amphinome pallasi Quatrefages, 1865 and Chloenea atlantica McIntosh, 1885 (Polychaeta Errantia, Amphinomorpha). Dokl. AN SSSR, 141, 3, 754-757
Sveshnikov, V A, 1959. Biology of propagation and development of the polychaetes of the White Sea. Diss Cand. University of Moskow
Ushakov, P V, 1955 Polychaete worms from the far eastern seas of SSSR. Determination for the fauna of SSSR. Izd. Zool. Inst. AN SSSR 56: 1-445
Ushakov, P V and Bao-Lin, U, 1960, Preliminary account on the polychaete worm fauna of Chinese Seas. Oceanol. Limnol. sinica, 3, 2, 86-93.