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Notice: ©1981 The Ichthyological Society of Japan. This article may be cited as: Mok, H.-K. (1981). The posterior cardinal veins and kidneys of fishes, with notes on their phylogenetic significance. Japanese Journal of Ichthyology, 27(4), 281-290.

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Japanese Journal of Ichthyology Vol. 27, No.4 1981

The Posterior Cardinal Veins and Kidneys of Fishes, with Notes on Their Phylogenetic Significance

Hin-Kiu Mok (Received November 27, 1979)

Abstract The variations of the relation and relative size of the posterior cardinal veins and the fusion of the left and right kidneys in seme major fish groups are described. The morphological variations of these characters in the two systems are interpreted and hypotheses concerning the phylogenetic interrelationships of the fish groups are made. The neoposterior cardinal veins being equally long is treated as a plesiomorphic character state for actinopterygians. In the vast majority of these fishes the right neoposterior cardinal vein is much longer and larger in diameter than the left one. The left neoposterior cardinal vein of osteoglossomorphs (including hiodontids) is larger and longer than the right. This synapomorphic character state supports their monophyletic relationships. The presence of a connection between the hepatic and neoposterior cardinal vein in brachiopterygians suggests' their affinity with other sarcopterygians. The presence of an anterior median sinus in chondrichthyans formed by the fused parts of the anterior neoposterior cardinal veins may be synapornorphic for gnathostomes and indicates the monophyly of chondrichthyans. Complete separation of the left and right kidneys which is here hypothesized as an apo­ morphic character state of the gnathostome kidney morphology has appeared at least three times in this fish group. This character state casts light on the monophyly of Brachio­ pterygii, Dipnoi, and Tetrapoda. Occurrence ofsimilar character states in other gnathostomes is due to convergence.

While conducting a survey of gnathostome After the removal of these organs, the kidney kidney morphology, I noticed some morpho­ could be easily observed. The posterior car­ logical variations in the posterior cardinal vein dinal veins are embedded on the surface of system and the fusion of the left and right the left and right kidneys. The shape of the kidneys (Mok, 1978). The phylogenetic signifi­ kidney, the size, length, and relation of the cance of these diversities have not been suf­ left and right posterior cardinal veins were ficiently exploited. Therefore, I undertook a recorded. preliminary review of these two systems with Specimens examined: Chimaeridae: Chi­ special attention to the application of these maera phantasma, AMNH uncat., 150 mm TL morphological variations to reconstruct the (total length). Dasyatidae: Taeniura meyeni, phylogenetic history of gnathostomes. AMNH uncat., 150 mm TL. Squalidae: Squa­ Ius acanthias, AMNH 1023, 160 mm TL. Lati­ Materials and methods meriidae: Latimeria chalumnae, AMNH 36941, The specimens examined in the present 1300 mm TL. Lepidosirenidae: Lepidosiren study are from the Ichthyology Department, paradoxa, GD 7.068.1, 540mm TL. Polypter­ American Museum of Natural History idae: Calamoichthys calabaricus, AMNH un­ (AMNH); personal collections of Dr. Peter cat., 190 mrn, 240 mm TL; ornati­ Moller (PM) of the City University of New pinnis, AMNH 6349, 108 mm TL; Polypterus York, and Mr. Guido Dingerkus (GD) of the palmas, AMNH 6300, 110 mm, 114 mm TL. Ichthyology Department, American Museum Acipenseridae: Acipenser stellatus, AMNH of Natural History. One or more individuals 20694, 157 mm TL. Polyodontidae: Polyodon of each species studied were examined. The spathula, AMNH uncat., 288mm TL. Lepiso­ viscera including the gastrointestinal tract and steidae: Lepisosteus oculatus, AMNH 37370, the swimbladder (if present) were removed. 148 mm TL; Lepisosteus platyrhincus, AMNH

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27734, 237 mm TL. Amiidae: Amia calva, "We have no evidece to show whether this AMNH uncat., 107 mm TL. Osteoglossidae: single interrenal posterior cardinal vein in Osteoglossum bicirrhosum, AMNH uncat., 75 Squalus is formed by the fusion of the two mm, 80 mm SL (standard length). Pantodon­ limbs of the loop (loop of Jacobson), or tidae: Pantodon buchholzi, AMNH uncat., whether only one of them persists, as for 75 mm SL. Hiodontidae: Hiodon alosoides, example in Mustelus antarcticus and Noto­ AMNH 23754, 60 mm, 67 mm SL. Notopteri­ rhynchus maculatus." dae: Notopterus sp., AMNH uncat., 150 mm, Besides the posterior fusion of neoposterior 160 mm SL; Xenomystus nigri, AMNH uncat., cardinal veins, a spacious medial sinus may 150 mm, 160 mm SL. Gymarchidae: Gymnar­ be frequetly formed by the fused anterior chus niloticus, PM uncat., 312 mm TL. Mormy­ portion of the neoposterior cardinal veins in ridae: Gnathonemus sp., AMNH 19671, 110 chondrichthyans, such as Squalus acanthias, mm TL; Mormyrops deliciosus, AMNH 6892, S. sucklii, Scyllium canicula (O'Donoghue, 142 mm SL; Petrocephalus sp., AMNH 6885, 1914; O'Donoghue and Abbott, 1928: fig. lB), 84 mm SL. Anguillidae: Anguilla rostrata, Raja nasuta (Parker, 1881), and Hydrolagus AMNH 36091, 283 mm TL. colliei (Stahl, 1967). This anterior sinus is insignificant in Mustelus antarcticus (Parker, Results 1886: pI. 34). The time of its appearance is Posterior cardinal vein system. The pos­ variable. It develops in late embryonic stages terior cardinal vein system of primitive gnatho­ in Scyllium canicula (O'Donoghue and Abbott, stomes consists of (I) the paired renal portal 1928), but does not appear until maturation veins representing the posterior part of the in Squalus (Walker, 1956). protoposterior cardinal veins, present in chon­ There are resemblances between the posterior drichthyan embryonic stage and in adult cycle­ cardinal vein system of holocephalian fish stomes (see below), (2) the medial unpaired (Hydrolagus colliei) and the elasmobranchs. caudal vein joining the renal portal vein at In the former, there are numerous, sizable its anterior end, and (3) the paired neoposterior communications between the left and right cardinal vein which is a composite of the neoposterior cardinal veins, and posteriorly at subcardinal vein and the anterior section of the origin of the trunk between the kidneys, the protoposterior cardinal vein (Smith, 1960). there is a single median vein, the interrenal In elasmobranchs such as Squalus, a con­ vein (Stahl, 1967). Stahl made no mention nection between the anterior section of the of the composition of the interrenal vein. protoposterior cardinal vein and the subcar­ There are some generalized characters of dinal vein on each side is formed early in the chondrichthyan posterior cardinal vein ontogeny (Walker, 1956: fig. lA). The left system: (I) the left and right neoposterior and right subcardinal veins communicate cardinal veins are recognizable and equal in medially by some short cross anastomoses at length; (2) the posterior parts of these veins their posterior sections and have no connec­ are connected by anastomoses; (3) a median tion to the posterior sections of the proto­ anterior sinus is present; (4) the extreme an­ posterior cardinal veins. These anastomoses terior sections of these veins (or the neo­ may be absent in the adult, e.g., Squalus posterior cardinal sinuses) tend to increase in acanthias, S. sucklii (O'Donoghue and Abbott, diameter. The primitive nature of the first 1928), and Scyllium canicula (O'Donoghue, character state is indicated by the presence of 1914). A medial interrenal vein is present neoposterior cardinal veins of equal length in posteriorly in S. canicula (O'Douoghue and both embryonic and adult stages of some Abbott, 1928: fig. IB). This vein is com­ elasmobranchs (e.g., Walker, 1956). Reduction posed of the fused posterior (or the subcardinal) in length of either one of these veins, or sections of the neoposterior cardinals or of longitudinal fusion of their posterior sections, one of these veins when the other has lost has also been observed in chondrichthyans. its posterior section. O'Donoghue and Abbott The left neoposterior cardinal vein is shortened (1928 : 873) wrote about the interrenal vein, in Mustelus antarcticus; the short left neo-

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apC'V ,- h eev ./ hv npev sv ms ppcv an rpv


ev A B

Fig. I. Simplified diagram of the posterior cardinal vein system in (A) Squalus sp. (late embryonic stage; after Walker , 1956) and (B) Scyllium canicula (after O'Donoghue and Abbott, 1928). an, anastmosis; apcv, anterior protoposterior cardinal vein; ccv, common cardinal vein; cv, caudal vein; h, heart; hv, hepatic vein; iv, interrenal vein; ms, medial sinus of the fused neoposterior cardinal veins; npcv, neoposterior cardinal vein; ppcv, posterior protoposterior cardinal vein; rpv, renal portal vein; sv, subcardinal vein. posterior cardinal vein has short transverse protopostcava which exists in all living tetra­ anastomoses joining the long right one, which pods (except mammals), dipnoans, polypterids, is also larger in diameter (Parker, 1886). and coelacanths (also see below), the sub­ Burne (1923: 246) observed a reduction in cardinal (or the posterior) portions of the neo­ neoposterior cardinal length in Lamna nasus posterior cardinal veins tend to fuse medially and wrote, "It is clear that the posterior car­ giving rise to a medial vein (Smith, 1960), dinal vein system has to all intents and pur­ which joins the right hepatic vein forming the poses been eliminated, so far as the trunk protopostcava. Except for modern urodeles, circulation is concerned and its place taken the anterior sections of the neoposterior car­ by the subrenal rete and lower lateral cutane­ dinal veins are sepa rate from the protopost­ ous vein." In order to decide the nature cava. In modern urodeles, these sections of (advancement or primitiveness) of the chon­ the neoposterior cardinal veins retain their drichthyan interrenal vein, more studies have connections with the protopostcava .'only in to be made. ·The possession of the interrenal its early developmental stage. Unlike chon­ vein might be apomorphic since it is absent drichthyans, this anterior fused area of the not only from the embryonic stage (e.g. Squalus; neoposterior cardinal veins in modern urodeles Walker, 1956), but also from the adult stage does not enlarge to form a sinus. As such, (e.g., Raja nasuta; Parker, 1881) of some the presence of an anterior median sinus may elasmobranchs. However, because of its pre­ be apomorphic for vertebrates, supporting the / sence in holocephalians, outgroup comparison monophyly of chondrichthyans. There is no provides a conflicting view to the above inter­ fusion of the subcardinal portions of the neo­ pretation. posterior cardinal veins in .dipnoans, poly­ Medial fusion of the rear neoposterior pterids, and coelacanths. It seems that fusion cardinal veins also took place in the evolution of the neoposterior cardinal veins has devel­ of the .postcava in tetrapods. Therefore, the oped twice in vertebrates (chondrichthyans nature of the interrenal in chondrichthyans and tetrapods). There is not enough infor­ is obscure. During the evolution of the mation at the present time to determine

- 283 - Japan. J. Ichthyol. 27(4), 1981


A B c D

, ~ ~ . ~ ...",:, .. ...(". ' ; ~,n"

. "" ..

E F G H Fig. 2. Arrangement of posterior cardinal veins on the kidneys which are shown in the ventral view. A: Polypterus ornatipinnis, B: P. palmas. C: Calamoichythyscalabaricus, D: Anguilla rostrata. E: Acipenserstellatus. F : Polyodon spathula. G: Lepisosteus ocula­ tus. H: Amia calva, ak , anterior kidney; an, anastomose; lncv, left neoposterior car­ dinal vein; pk, posterior kidney ; rncv, right neoposterior cardinal vein.

whether it represents a plesiomorphic character left neoposterior cardinal vein and the proto­ state of gnathostomes. postcave of Protopterus annectens and Lepido­ In dipnoans, e.g., Protopterus anneetens, siren paradoxa are connected by several cross the large protopostcava, which is a composite anastomoses along their length. of the right hepatic vein and the subcardinal The neoposterior cardinal veins ofPolypterus portion of the right neoposterior cardinal vein, spp. and Calamoichthys calabaricus are asym­ is connected to the left neoposterior cardinal metrical in diameter and length. The left vein by several transverse anastomoses (Parker, vein was not observed in Polypterus ornati­ 1892). Both veins of this species are equally pinnis and C. calabaricus. In t}{e former long. A vein homologous to the dipnoan proto­ species, the right neoposterior cardinal vein postcava has been reported by Robineau and branches into two at the mid-section of the Anthony (1971) in Latimeria chalumnae. This right kidney; the left branch crosses to the species is slightly different from Protopterus left kidney and runs to the posterior end of annectens in that the left neoposterior cardinal the peritoneal cavity, where it connects to the vein drains directly into the posterior section distal end of the hepatic vein (Fig. 2A). In of the protopostcava, without anastomoses P. palmas and C. calabaricus, the right neo­ (Robineau and Anthony, 1971), whereas the posterior cardinal vein crosses to the left

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.:>. Mok : Posterior Cardinal Veins and Kidneys

kidney at the mid-section of the right kidney dipnoans and coelacanths, in which the hepatic and extends posteriorly to the rear end of the vein connects to the anterior end of the pos­ left kidney where it connects to the hepatic terior part of the right neoposterior cardinal vein. The left neoposterior cardinal vein is vein, can hardly be derived from the condition present in P. palmas. It is short and does of the polypterids, in which the posterior ends not drain into the distal end of the right neo­ of these veins join. posterior cardinal vein which is also in the The two neoposterior cardinal veins in left kidney (Fig. 2B, C). Kerr (1910) seems chondrosteans and ginglymods do not differ to be the only worker who reported the same significantly in length. In Acipenser stellatus observation. He (1910: 104) stated, "The and Polyodon spathula, the left one is longer hepatic vein is of great size and the main (Fig. 2E, F), whereas it is only slightly longer trunk of it traverses the liver right to its in Lepisosteus oculatus and L. platyrhincus posterior end, and then runs free for a con­ (Fig. 20). Anastomoses are absent from these siderable distance through the splanchnocoele groups. along the right side of the right lung till it joins Interestingly, Amia calva does not resemble the interrenal vein which I have described as the other lower actinopterygians mentioned. a true primitive posterior vena cava of the The long right neoposterior cardinal vein same type as that in lungfishes and peculiar exists while the left one is absent (Fig. 2H). only in the fact its communication with the This character state is similar to higher interrenal (posterior cardinal) vein is further neopterygians in that the right neoposterior back than usual." cardinal vein is much longer than the left, of The connection between the posterior ends which only a short section drains the left ex­ of the right neoposterior cardinal vein and the treme anterior kidney. hepatic vein at the posterior end of the perito­ In the vast majority of teleostean kidneys, neal cavity and the degeneration of the left the right neoposterior cardinal vein is the neoposterior cardinal vein distinguish polypte­ major vein. The left one is much smaller, rids from coelacanths and dipnoans. The con­ both in diameter and in length, and in some nection between the hepatic and neoposterior cases is absent (Ogawa, 1961; Mok, 1978). cardinal veins is an advanced character relative In most teleosts, there is no anastomosis be­ to that of the actinopterygians and the chon­ tween these veins, although in some cases, drichthyans in which these veins remain sepa­ e.g., Anguilla rostrata, some small branches rate. Two opposite views regarding the nature from the right neoposterior cardinal vein run of the character of polypterids are proposed: transversely to the left kidney, but do not either it is the plesiomorphic state of sarcopter­ connect to the short left neoposterior cardinal ygians under the assumption that the charac­ 'vein (Fig. 2D). Jollie (1962), however, showed ters of polypterids and other sarcopterygians are that in salmons two transverse anastomoses homologous; or it is an autapomorphic charac­ connect the large right and short left neopos­ ter of vertebrates. Under the former hypo­ terior cardinal veins. thesis, coelacanths would appear more closely In most osteoglossomorphs, the left neopos­ related to dipnoans and tetrapods than are terior cardinal vein is much longer than the polypterids; and these four taxa would appear right (Fig. 3A~I). Gymnarchus niloticus is to form a monophyletic group. The latter an exception in that a branch from the anterior hypothesis is uninformative concerning the section of the long right neoposterior cardinal phylogenetic position of the polypterids, but vein runs transversely to the left kidney and it indicates the rnonophyly of coelacanths, continues to its posterior section (Fig. 2F). dipnoans, and tetrapods. If information about Although the osteoglossomorph condition is the posterior cardinal vein systems of juvenile somewhat similar to that of the chondrosteans, coelacanths, dipnoans, and polypterids were I suggest that it has developed independently available, one would be able to decide between in these groups and that it is an advanced these two hypotheses. The second hypothesis actinopterygian character state. The left side seems more likely because the adult condition of branch of G. niloticus is autapomorphic.

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.... 't


A c D E

r n c v-·

F G H Fig. 3. Arrangement of posterior cardinal veins on the osteoglossomorph kidneys which are shown in the ventral view . A: Osteoglossum bicirrhosum. B: Pantodon buchholzi. C: Hiodon alosoides . D: Notopterus ,sp. E: Xenom ystus nigri. F: Gymnarchus niloticus. G: Gnathonemus sp. H: Morm yrops delicio sus. I: Petrocephalus sp. ak , anterior kidney ; lncv, left neoposterior cardinal vein ; pk, posterior kidney; rncv, righ ~ neoposterior cardinal vein.

-,1 However. its long right neoposterior cardinal reduced in size or may even be absent as in branch reflects its similarity to other teleostean B. dombeyi; (5) a connection between the patterns. caudal vein and the protoposterior cardinal Cyclostomes lack subcardinal veins (Smith . veins is present (equivalent to the connection 1960). Hagfishes, such as Myxine glutinosa of the caudal vein and the renal portal veins and Bdellostoma dombeyi, resemble each other of gnathostomes; Jackson. 1901; Johansen. in their posterior cardinal system in that (I) 1963). Lampreys are different in some aspects the left protoposterior cardinal vein is con­ from the hagfishes: (I ) the right protoposterior siderably larger than the right; (2) they are cardinal is larger than the left; .(2) the left joined by a large number of short transverse protoposterior cardinal vein joins the right commissural vessels located along their length; just posterior to the level of the heart and (3) the common protoposterior cardinal vein both cardinals drain into the sinus venosus (the anterior section of the left protoposterior through the right duct of Cuvier (Jollie, 1962). cardinal vein) passes forward to the left side Cyclostomes in general are characterized by and empties into the posterior end of the (I) the absence of subcardinals, (2) the presence sinus venosus; (4) the anterior section of the of anastomoses. and (3) asymmetrical develop­ right protoposterior cardinal vein is much ment of the two protopostererior cardinals

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'- .:,:. ' -. . . Mok : Posterior Cardinal Veins and Kidneys

non- batoid BotoideQ Holo- tn-o- Dipnoi Brachio­ Coeolacan­ Ad [no­ n oosetachians cephaiia poaa ptE'rygii thiforme 5 Plerygii

Fig. 4. Cladogram of the major groups of vertebrates on the basis of the kidney morphology and other characters studied by previous workers. Distribution of the two character states of the connection between the left and right kidneys (f: fused; s: separate) in living groups (0) and hypothetical ancestors are listed.

and the extreme anterior end of these veins. be the same condition that occurs in Proto­ Smith (1960) suggested that the absence of pterus annectens, wherein the posterior parts subcardinals in cyclostomes is secondary. In of the kidneys near the urinary bladder are the lack of ontogenetic evidence, it would seem "fused" superficially. They are, in fact, reasonable to say that the nature of this charac­ separate and are only connected by the lym­ ter (absence of these veins) is still obscure. phoadenoid tissue that coats these organs Fusion of the left and right kidneys. Com­ (Parker, 1892). plete separation of the left and right kidneys For the other living gnathostomes (including occurs in some batoids (e.g., Taeniura meyeni, chimaeras, non-batoid neoselachians, some AMNH uncat., 150 mm TL, personal observa­ batoids, coelacanthiforms, actinopterygians), tion), dipnoans, such as Protopterus annectens the posterior kidneys or the extreme posterior (Parker, 1892: pI. 5), Lepidosiren paradoxa kidneys are fused to various degrees. The (Kerr, 1901; personal observation was made kidney of Latimeria chalumnae is specialized on a 540 mm TL specimen, GD 7.068.1), poly­ in that only the extreme posterior parts (or pterids (both Polypterus spp. and Calamoichthys the extreme posterior kidneys) are present calabaricus) and some euteleosts (Budgett, (personal observation, AMNH 36941, 1300 mm 1901; Mok, 1978). Whether all dipnoans have TL; Millot and Anthony, 1973). They are the same kidney morphology, namely, com­ fused medially, placed on the floor at the plete separation of the left and right com­ posterior end of the peritoneal cavity. For ponents of the kidney, is not certain. Ballan­ cyclostomes, the kidney structure is strikingly tyne (1928) wrote about this organ in Neo­ different from that of gnathostomes (Fange, ceratodus forsteri: "Two kidneys are fused for 1963). Therefore, comparison between the a short distance at the level where the most cyclostome and gnathostome kidneys at the anterior vasa efferentia open into the kidney gross structural level provides no information tissue." Since there is no illustration in his for determining the nature of the two character paper, the exact position of fusion is not states (complete separation versus partly fusion) known. Whether the kidneys are really fused of gnathostome kidneys. in this species is doubtful to me. It might With regard to the distribution of these

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character states (fusion and separation of the tetrapods is synapomorphic, indicating the kidneys) among gnathostomes, a hypothesis monophyly of these groups. However, the concerning the sarcopterygian interrelation­ difference in the manner ofconnection between ships can be reached. This hypothesis is the the hepatic and neoposterior cardinal vein of most parsimonious one involving a minimum polypterids and the other aforementioned number of kidney character state reversals groups raises questions concerning the homo­ (Fig. 4). The Coelacanthiformes are considered logy of these structures. Data about the as the plesiomorphic sister-group of a mono­ development of this connection in polypterids phyletic assemblage that includes the Dipnoi, would be helpful in answering these questions. Brachiopterygii, and Tetrapoda. In the latter The monophyly of tetrapods, dipnoans, and group rnonophyly is indicated by the complete polypterids, indicated by kidney fusion, fits separation of the kidneys. I suggest that with the evidence of Miles (1977). With kidney separation in some batoids has evolved regard to the two hypotheses of the hepatic independently. and neoposterior cardinal veins connection, the hypothesis that the polypterid character Discussion state is plesiomorphic in sarcopterygians (see The interrelationships of sarcopterygians above) conflicts with the evidence of kidney have been widely discussed, but are not agreed fusion. If the polypterid character is autapo­ upon. Dipnoans, for example, are of uncertain morphic, this particular venous character and relationships (Moy-Thomas and Miles, 1971); kidney fusion do not conflict. On the basis it has been hypothesized that they are closely of the present data, I favor the latter hypothesis related to the Crossopterygii (e.g., Westoll, that the polypterid character is autapornorphic. 1949; McAllister, 1968; and Gardiner, 1973); to Neoposterior cardinal veins being equally the (Bertmer, 1966), to choanates long is plesiomorphic for actinopterygians. (Miles, 1977), or that they are a separate group Halecostomes (including halecomorphs and related to the common stock ofcrossopterygians teleosts) seem to be a monophyletic group, and actinopterygians. As for the systematic because they share the apornorphic character position of crossopterygians, Bjerring (1973) state that the right neoposterior cardinal vein argued against the monophyly of the eros­ is much longer than the left. A similar state sopterygians and suggested that coelacanthi­ in some elasmobranchs seem to be convergence. forms are not members of this group on the The transverse connection between the neo­ basis of the differences in their cranial sub­ posterior cardinal veins by anastomoses is divisions. However, he did not make further ·plesiomorphic for gnathostomes. The loss of suggestions concerning the relationship of this connection in most actinopterygians would coelacanthiforms. The systematic position of seem to be apomorphic at certain levels within polypterids is also equivocal. Pehrson (1947), this group. Stensio (1947), DeBont and Paulus (1964), There has been conflict of opinion concern­ McAllister (1968), and Gardiner (1973) agreed ing the phylogenetic relationship of the Hi­ upon the actinopterygian affinity of polypterids. odontidae. McAllister (1968) erected a new Nelson (1969, 1973), on the other hand, placed suborder for this family, separated it from them in the subclass Sarcopterygii on the basis the group that includes the Osteoglossidae, of the evidence of gill arch and jaw structures. Pantodontidae. Notopteridae, Mormyridae, Jessen (1973) remarked that the shoulder girdle and Gymnarchidae, and considered it to be and pectoral fin of Polypterus show no simi­ a relative of the elopoids, albuloids, or clu­ larities at all with those of actinopterygians, peoids by the shared character of the otophysic which are clearly distinguishable from poly­ connection of the swimbladder diverticuli. pterids and occupy a position of their own In contrast, Ridewood (1904, 1905), Regan among fishes in general. (1929), Berg (1940), Gosline (1960), and Green­ I suggest that the presence of a connection wood (1963) have agreed that the Hiodontidae between the hepatic and neoposterior cardinal forms part of a single group that includes the vein in coelacanths, polypterids, dipnoans, and above mentioned families. Greenwood et al.

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(1966) have called it the Osteoglossomorpha. noan posterior nostrils. Acta. Zool. Stockh., McAllister's hypothesis has recently been con­ 47: 81~150. Bjerring, H. C. 1973. Relationships of coel­ tested by Nelson (1972) on the basis of a gut acanthiforms. In Greenwood, P. H., R. S. Miles character shared by these families, including and C. Patterson, eds.: Interrelationships of the Hiodontidae: the anterior section of the fishes. Academic Press, New York, 536pp. intestine passes posteriorly to the left rather Budgett, J. S. 1901. On some points in the than the right of the esophagus and stomach. anatomy of Polypterus. Trans. Zool. Soc. Lon­ This evidence led Nelson (1972) to the conclu­ don, 15(7): 325~338. sion that the Osteoglossomorpha are a mono­ Burne, R. H. 1923. Some peculiarities of the phyletic group. The posterior cardinal vein blood-vascular system of the porbeagle shark system supports the osteoglossomorph affinity (Lamna cornubica). Phil. Trans. Roy. Soc. of the Hiodontidae. The left neoposterior London, 212: 209~257. DeBont, A. F. and J. Paulus. 1964. Electro­ cardinal vein being larger or longer than the phoretic characteristics of the serum of some right, a character shared by the osteoglosso­ African freshwater fishes. Verh. Tnt. Vert. morphs including hiodontids, is apomorphic Limnol., 15: 976~980. within halecostomes and suggests the osteo­ Fange, R. 1963. Structure and function of the glossomorph affinity of the Hiodontidae. excretory organs of myxinoids. In Brodal, A. and R. Hinge, eds.: The biology of Myxine. Acknowledgments Universitetsforlaget, Oslo, 588pp. This report is derived from a dissertation Gardiner, B. G. 1973. Interrelationships of tele­ submitted in partial fulfillment of the require­ ostomes. In Greenwood, P. H., R. S. Miles and ments for the degree of Doctor of Philosophy C. Patterson, eds.: Interrelationships of fishes. at the City Uinversity of New York. I wish to Academic Press, New York, 536 pp. Gosline, W. A. 1960. Contributions toward a thank my major advisor, Dr. Gareth J. Nelson classification of modern isospondylous fishes. of the American Museum of Natural History, Bull. Brit. Mus. (Nat. Hist.), Zool., 6(6): 325~ for his inspiration and guidance. Thanks also 365. go to Drs. Donn E. Rosen of the American Greenwood, P. H. 1963. The swimbladder in Museum of Natural History and Gareth J. African Notopteridae (Pisces) and its bearing Nelson for their permission to dissect the on- the of the family. Bull. Brit. coelacanth specimen. Dr. Peter Moller of Mus. (Nat. Hist.), Zool., 11(5): 377~412. the American Museum of Natural History Greenwood, P. H., D. E. Rosen, S. H. Weitzman and Mr. Guido Dingerkus of the New York and G. S. Myers. 1966. Phyletic studies of Aquarium kindly allowed me to examine teleostean fishes, with a provisional classification specimens in their personal collection. Dr. of living forms. Bull. Amer. Mus. Nat. Hist., 131(4): 339~456. Gareth J. Nelson, Mr. Guido Dingerkus, and Jackson, C. M. 1901. An investigation of the Mr. Grant Gilmore of the Harbor Branch vascular system of Bdellostoma dombeyi. J. Cin. Foundation kindly reviewed the draft manu­ Soc. Nat. Hist., 20(1): 13~47. script. This paper is Contribution No. 197 of Jessen, H. L. 1973. Interrelationships of acti­ the Harbor Branch Foundation, Inc. nopterygians and brachiopterygians: evidence from pectoral anatomy. In Greenwood, P. H., Literature cited R. S. Miles and C. Patterson, eds.: Interrela­ Ballantyne, F. M. 1928. Note on the male tionships ot fishes. Academic Press, New York, genito-urinary organs of Ceratodus forsteri. 536pp. , Proc. Zool. Soc. London, 1928: 697~698. Johansen, K. 1963. The cardiovascular system Berg, L. S. 1940. Classification of fishes both of Myxine glutinosa L. In Brodal, A. and R. Recent and fossil. Trav. Inst. Zool. Acad. Fange, eds.: The biology of My xine, Univer­ Sci., U.S.S.R., 5(2): 1~517. (Russian and sitetsforlaget, Oslo, 588 pp. English texts; also reprint, Ann Arbor, Michi­ Jollie, M. 1962. morphology. Rein­ gan, 1947). hold Publ. Co., New York, 478 pp. Bertmer, G. 1966. The development of skeleton, Kerr, J. G. 1901. The development of Lepido­ blood-vessels and nerves in the dipnoan snout, siren paradoxa. Part II. Quart. J. Micro. Sci., with a discussion on the homology of the dip- 29(1): 1~40.