10 p. : ill. ; 24 cm.Includes bibliographical references

Goffin, Robert A.

Gudger, E. W. (Eugene Willis), 1866-1956.

American Museum of Natural History Scientific Publications

AMERICAN MUSEUM NOVITATESPublished byNumber 600 THE AmERICAN MUSeUM OF NATURAL HISTORY March 21, 193359.7, 35 R: 12.7A SECOND BARN-DOOR SKATE, RAJA STABULIFORIS, WITHPECTORALS NON-ADHERENT TO THE HEADBy E. W. GUDGERIt is interesting to note that two specimens of the same skate,having exactly the same type of abnormality, have been captured in thesame general locality, Woods Hole, Massachusetts, by the same collector,Mr. Robert A. Goffin of the Bureau of Fisheries station. Moreover,both fish are males. The first was taken in 1924 in a fish-trap in Menem-sha Bight, east of Gay Head in Vineyard Sound. The second was cap-tured with an otter-trawl on December 1931, about 20 fathoms down andabout 25 miles southwest of Nantucket Island. The first specimen is inthe collections of the U. S. National Museum at Washington. With thepermission of the officials of the Bureau of Fisheries, the second speci-men was presented by Mr. Goffin to the American Museum, and is nowin my keeping.THE FIRST DEFORMED SKATEThe first specimen (1924) was identified by Mr. Lewis Radcliffeand was described by him in an article published in Natural History in1928.1 It will be well briefly to redescribe this first specimen, shownherein in dorsal and ventral views in figures 1 and 2, in order thatdirect comparisons may be made of it with the present specimen.As the figures show, it is an immature male with the pectoralsseparated from the head by deep and wide notches. The completemeasurements of this specimen will presently be set alongside those ofthe second fish. Here it is enough to say that the fish shown in figures1 and 2 is 20.5 inches long over all, and 12.75 inches wide; while thelength of the head, from tip of snout to the midpoint of line joining thebases of the right and left notches, is 5.25 inches. The right notch isslightly deeper than the left-5.5 inches right and 5.25 inches left.From this, and from the figures, it is seen that the fish is slightly asym-metrical. This asymmetry is even more plainly seeu when one considersthe relative position of the gill-slits as shown in figure 2. On the leftiRaddliffe, Lewis, 1928. 'A Barn-door Skate (Raja stabuliforis) with Abnormal Pectoral Fins.'Nat. Hist., XXVIII, pp. 58-63, 7 text-figs.AMERICAN MUSEUM NOVITATESside two slits are shown anterior to the notch where head and pectoralmeet, while on the right there are three slits above the notch. Otherthan in these points named, this young ray seems entirely normal.Fig. 1 Fig. 2Fig. 1. Dorsal aspect of Raja stabuliforis (No. I) from Woods Hole. The headand pointed pectorals are separated by wide notches, that on the right being deeper.After Radcliffe, 1928.Fig. 2. Ventral view of abnormal barn-door skate No. I. The right-hand notchhas three gill-slits above it; the left notch has but two.After Radcliffe, 1928.THE SECOND MALFORMED SKATEThe second ray is shown in both dorsal and ventral view in figures3 and 4. It is also an immature male, as the very small claspers indicate,and is in the same stage of development as is the preceding. It measures19 inches over all, and 12.25 inches in extreme breadth. The head fromthe extremity of the snout to the midpoint of a line joining the notchesis 4.75 inches long. Like fish No. I, the right-side notch is deeper thanthe left-5.25 inches compared with 4.9.Not so apparent as the wide notches between head and pectorals,but even more interesting, is the number and position of the gill-slits.On the left side there are five, decreasing somewhat uniformly in sizefrom front to rear, the fifth being only about half as wide as the first.Unlike those of the first specimen, which has two gill-clefts anterior tothe notch, all these are located well behind the notch on the left side.Those on the right side, however, are only four in number, and two ofthese are located above the notch, the third slightly below the base ofthe notch, and the fourth well behind this. Slits one and two on the2 [No. 6001933] AN ABNORMAL FORM OF RAJA STABULIFORISright side are about of a size, and only about half the size of slit numberthree; the largest, number four, is also about equal in size to numbersone and two. Most remarkable of all is the fact that, in the hinder wallNofgill-slit number four, there is the rudiment of the last (fifth) right gill-slit.The opening is there, as may be seen in figure 4, about one-third as wideas is that of gill-slit number four. This slit ends in a blind sac about one-Fig. 3. Dorsal view of bar-door skate No. II from Woods Hole. The ab-normality is identical with that of specimen No. I, the right notch being deeper.fourth inch beneath the surface. It should be noted before leaving thesestructures that the right gill-slit of fish No. I is of about the same sizeand width as right gill-slit three of the present specimen.The base of the notch on the left side of specimen No. II is 4.9 in.from the end of the snout, while the first gill-slit on that side is 5 in.3AMERICAN MUSEUM NOVITATESfrom the same point. The base of the right notch is about 5.25 in. fromthe tip of the snout, and the first gill-slit is about 4.9 in. from the samepoint of reference. Gill-slits number two are about the same distancefrom the tip of the snout, and are about opposite each other (see Fig. 4).The gill-slits on the right seem nearer the tip of snout because of thedeeper cleft on that side.Fig. 4. Ventral aspect of ray No. II. Two right gill-slits are above the notch,the third is even with it, the fourth and the included fifth are below. On the left allfive are well below the notch.Other than in the matter of the notches on the right and left sides ofthe head, the relative size of the gill-clefts, and particularly in thematter of the rudimentary fifth slit on the right, this second young speci-men of the barn-door skate seems normal.4 [No. 6001933] AN ABNORMAL FORM OF RAJA STABULIFORISIn the table the relative measurements of the two specimens arecontrasted. Ray No. I is Radcliffe's specimen, while No. II is mine.The measurements are all made in straight lines and recorded in inches.MEASUREMENTS OF RAYS WITH NON-ADHERENT PECTORALSRay Number I IILength over all 20. 5 in. 19.O in.Length body proper (snout to hinder edge vent) 9.8 in. 9.4 in.Length tail (hinder edge vent to tip) 10.7 in. 9.6 in.Length snout tip to midpoint of line joining notches 5.25 in. 4.75 in.,ength snout tip to right-side first gill-slit 4.9 in. 5.00 in.Length snout tip to left-side first gill-slit 4.7 in. 4.9 in.Length right horn of pectoral to base of cleft 3.0 in. 2.75 in.Length left horn of pectoral to base of cleft 2.75 in. 2.4 in.Width over all 12.75 in. 12.25 in.Width head at bottom shallow cleft 3.25 in. 3.25 in.Width between eyes 1. 0 in. 0. 9 in.Width tip to tip horns of pectorals 7.25 in. 7.1 in.Width tip to tip pelvics 5.6 in. 5.5 in.Depth snout to base right notch 5.5 in. 5.25 in.Depth snout to base left notch 5.25 in. 4.9 in.HISTORICAL NOTESThere is a rather extensive literature of this pectoral abnormality inskates and rays. This goes far back, even to the earliest printed worksdealing generally with fishes-those great folios in which were laid thefoundations of the natural history of fishes. However, this is not theplace to figure and describe, or even refer to the bishopfish, monkfish,5AMERICAN MUSEUM NOVITATESor priestfish of Belon (1551), Rondelet (1554), Gesner (1558), andAldrovandi (1613 and 1640). Some of these figures show the influence ofmythological ideas, but were undoubtedly based on such malformed raysas are figured above. Such no doubt is that shown in figure 5, though ithas plainly been manipulated by hand and dried to form the monsteras portrayed by Aldrovandi. I have seen present-day manipulationsproduce comparable apparitions. Some day I hope to bring a largenumber of these figures together, as an interesting chapter in the historyof ichthyology.In modern ichthyological literature there is a large list of such terato-logical specimens extending from 1810 to 1932. Thus far, I have accumu-Fig. 5. The priestfish. A malformed, hand-manipulated, dried ray with whichthe artist took many liberties in his drawing.After Aldrovandi, 1613.lated 35 in my file marked "Malformed Rays." Close search through theliterature will undoubtedly bring others to light. I hope some time tobring together all these modern accounts with their interesting figuresin an article covering the field thoroughly. To do so now is beyond thepurpose of this short article. However, it may not be out of place to givethree short references, in order to make a historical setting for the mal-formations of the barn-door skate.Present-day knowledge of these monstrous forms began with anaccount of such a ray taken on the coast of Sicily and described in 1810by that strange genius, Constantine Rafinesque-Schmaltz.1 He thoughtit was a distinct genus and gave its characters as follows (free transla-lRafinesque-Schmaltz, C.S. 1810. 'Indice d'Ittiologia Siliciana.' Messina. (Cephaleuthurus, p. 61.)6 [No. 6001933] AN ABNORMAL FORM OF RAJA STABULIFORIStion): "Head free and separated from the lateral wings; eye and spiraclesunited [near to each other] and situated on the side of the head; twofins above the tail, none at the extremity." Then he adds: "This genusis most remarkable because of the characters exhibited by its free head,which in all other genera is united to the lateral or it may be pectoral,r . ciE4 E.Fig. 6. Propterygia hypostica, a so-called new genus and species of ray. Here asecond split has divided each pectoral fin into an anterior horn and a posterior fin.After Otto, 1821.7AMERICAN MUSEUM NOVITATESwings [fins]." He names his form Cephaleutherus maculatus, and notesthat its head is pointed and that the lateral fins are also pointed. He un-fortunately gives neither measurements nor figure.The next describer was the Breslau naturalist, A. W. Otto,' who in1818 obtained from a fisherman at Edinburgh one of the most greatlymalformed rays ever figured and described. As may be seen in figure 6,this differs markedly from our two Woods Hole specimens. First there isthe normal split between the head and pectorals; then in some way notclear the fins have become split again to form two forward-pointinganterior horns and the two lateral wings. Otto also thought that he hada new genus and species, which he named Propterygia hypostica. His fishFig. 7. Hieroptera abredonsi, the Aberdeen priestfish. It has the same typeof abnormality as that found in the Woods Hole specimens.After Fleming, 1841.was small-18 inches long (equally divided between body and tail) and13 inches wide. His figure was evidently made after the specimen hadbecome dried.The next specimen to be figured and described (so far as I can findout) dates twenty years- forward. In 1841, Flemming2 described, alsofrom Scottish waters, a teratological ray which he thought was a newgenus and species, and which he called Heiroptera abredonensis (thepriest-winged fish from Aberdeen). This is shown as figure 7 herein. Itis very like the two Woods Hole fish, and needs no further description.'Otto, A. W. 1821. 'Ueber eine neue Roche (Propterygia hypostica),' etc. Nova Acta Acad. Leo-poldino-Caroline, X, pp. 113-121, 2 plates.2Flemming, John. 1841, 'Description of a Species of Ray New to the British Fauna.' EdinburghNew Philos. Journ., XXXI, pp. 236-238, 2 plates.8 [No. 60019331 AN ABNORMAL FORM OF RAJA STABULIFORISFrom this time on, the literature becomes too voluminous and com-plex to be covered satisfactorily in this short article. It is my intentionlater to collect and present it in definite form with all the interestingfigures to show how, only after a period of 75 years, the matter wasthoroughly cleared up-by Theodore Gill in 1896.How THIs CONDITION COMES ABOUTThe explanation is to be found in the embryology of the skate. Theskates and rays are highly specialized forms of the great group Elasmo-branchii-forms which have evolved beyond the sharks by developingmodifications for bottom-living. To this end the round body of theshark has become flattened, the pectorals have become enormously en-Fig. 8. The angel shark, Rhina squatina, an intermediate form between sharkand ray. Note the permanent notch between pectorals and head.After Boulenger, 1904.larged and have become adherent to the neck and head region. In thisprocess, the gill-openings have been forced from a lateral to a ventralposition. In the angel shark, Rhina squatina, is found an excellent con-necting link. In it, as may be seen in figure 8, the body is much flattened,the gill-slits are on the ventral surface, and the pectorals (also the pelvics)have become greatly enlarged. However, the pectorals are not yetadherent to the head, but are separated from it by conspicuous notches.These are morphologically identical with the notches that separate the"wings" from the head of the specimens of Raja stabuliforis from WoodsHole.9AMERICAN MUSEUM NOVITATESThis matter will be made clearer by study of figure 9, which wasdrawn from the larval form of the sting-ray, Dasyatis say. This babyray I cut from the uterus of the mother at Beaufort,IN. C., many yearsago. In this Caesarean operation the head was unfortunately torn off.However, there are left the pectorals, widely divergent from the head-stalk. Since this specimen was collected, I have gotten fairly completesets of stages for other rays, and have personally found, what is of coursewell known, that in its development the baby ray "climbs its ownFig. 9. Larval form of sting-ray, Dasyatis say, in intermediate stage of develop-ment between shark and ray. The head is lacking but the fins have not yet grownfast to the head-stalk. The yolk-stalk is still present and is shown on the left.ancestral tree," and in doing so goes through a number of shark stages.As the larval ray grows older, it becomes less shark-like and more like aray, passing through the stages shown in figures 9 and 8. From this it isclear that the specimens of the barn-door skate described herein arecases of arrested development, of fixed larval forms, directly comparableto the perennibranchiate urodeles among amphibians.10 [No. 600

Abnormal form of Raja stabuliforis

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