AMERICAN MUSEUM NOVITATES

Published by

Tae AMERICAN Museum or NaTuraAL HIsTory
Number 600 cen one March 21, 1933

59.7, 35 R: 12.7

A SECOND BARN-DOOR SKATE, RAJA STABULIFORIS, WITH
PECTORALS NON-ADHERENT TO THE HEAD

By E. W. GupGER

It is interesting to note that two specimens of the same skate,
having exactly the same type of abnormality, have been captured in the .
same 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 and
about 25 miles southwest of Nantucket Island. The first specimen is in
the collections of the U. 8. National Museum at Washington. With the
permission of the officials of the Bureau of Fisheries, the second speci-
men was presented by Mr. Goffin to the American Museum, and is now
in my keeping.

THE First DEFORMED SKATE

The first specimen (1924) was identified by Mr. Lewis Radcliffe
and was described by him in an article published in Natural History in
1928.1 It will be well briefly to redescribe this first specimen, shown
herein in dorsal and ventral views in figures 1 and 2, in order that
direct. comparisons may be made of it with the present specimen.

As the figures show, it is an immature male with the pectorals
separated from the head by deep and wide notches. The complete
measurements of this specimen will presently be set alongside those of
the second fish. Here it is enough to say that the fish shown in figures
1 and 2 is 20.5 inches long over all, and 12.75 inches wide; while the
length of the head, from tip of snout to the midpoint of line joining the
bases of the right and left notches, is 5.25 inches. The right notch is
slightly 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 seen when one considers
the relative position of the gill-slits as shown in figure 2. On the left

ee See ee eo ee ee ee
1Radcliffe, Lewis, 1928. ‘A Barn-door Skate (Raja stabuliforis) with Abnormal Pectoral Fins.’
Nat. Hist., XXVIII, pp. 58-63, 7 text-figs.

2 AMERICAN MUSEUM NOVITATES [No. 600

side two slits are shown anterior to the notch where head and pectoral
meet, while on the right there are three slits above the notch. Other
than in these points named, this young ray seems entirely normal.

Fig. 1 Fig. 2
Fig. 1. Dorsal aspect of Raja stabuliforis (No. I) from Woods Hole. The head
and 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 notch

has three gill-slits above it; the left notch has but two.
After Radcliffe, 1928,

THE SECOND MALFORMED SKATE

The second ray is shown in both dorsal and ventral view in figures
3 and 4. It is alsoan immature male, as the very small claspers indicate,
and is in the same stage of development as is the preceding. It measures
19 inches over all, and 12.25 inches in extreme breadth. The head from
the extremity of the snout to the midpoint of a line joining the notches
is 4.75 inches long. Like fish No. I, the right-side notch is deeper than
the 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 size
from 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 to
the 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 of
these are located above the notch, the third slightly below the base of
the notch, and the fourth well behind this. Slits one and two on the

1933] AN ABNORMAL FORM OF RAJA STABULIFORIS 3

right side are about of a size, and only about half the size of slit number
three; the largest, number four, is also about equal in size to numbers
one andtwo. Most remarkable of all is the fact that, in the hinder walllof
gill-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 wide
as is that of gill-slit number four. This slit ends in a blind sac about one-

Fig. 3. Dorsal view of barn-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 these
structures that the right gill-slit of fish No. I is of about the same size
and width as right gill-slit three of the present specimen.

The base of the notch on the left side of specimen No. IT is 4.9 in.
from the end of the snout, while the first gill-slit on that side is 5 in.

4 AMERICAN MUSEUM NOVITATES [No. 600

from the same point. The base of the right notch is about 5.25 in. from
the tip of the snout, and the first gill-slit is about 4.9 in. from the same
point of reference. Gill-slits number two are about the same distance
from 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 the
deeper 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 all
five are well below the notch.

Other than in the matter of the notches on the right and left sides of
the head, the relative size of the gill-clefts, and particularly in the
matter of the rudimentary fifth slit on the right, this second young speci-
men of the barn-door skate seems normal.

1933] AN ABNORMAL FORM OF RAJA STABULIFORIS 5

In the table the relative measurements of the two specimens are
contrasted. 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 wirH Non-ADHERENT PECTORALS

Ray Number
Length over all
Length body proper (snout to hinder edge vent)
Length tail (hinder edge vent to tip)
Length snout tip to midpoint of line joining notches
Length snout tip to right-side first, gill-slit
Length snout tip to left-side first gill-slit
Length right horn of pectoral to base of cleft
Length left horn of pectoral to base of cleft
Width over all
Width head at bottom shallow cleft
Width between eyes
Width tip to tip horns of pectorals
Width tip to tip pelvics
Depth snout to base right notch

Depth snout to base left notch

HistroricaL NorTes

3.0 in.

2.75 in.

12.75 in.

3.25 in.

1.0 in.

7.25 in.

5.6 in.

5.5 in.

§.25 in.

II

19.0 in.

9.4 in.

9.6 in.

. | 4.75 in,

5.00 in.

4.9 in.

2.75 in.

2.4 in,

12.25 in.

3.25 in.

0.9 in.
7.1 in.

5.5 in.

5.25 in.

4.9 in.

There is a rather extensive literature of this pectoral abnormality in
skates and rays. This goes far back, even to the earliest printed works
dealing generally with fishes—those great folios in which were laid the
foundations of the natural history of fishes. However, this is not the
place to figure and describe, or even refer to the bishopfish, monkfish,

6 AMERICAN MUSEUM NOVITATES [No. 600

or priestfish of Belon (1551), Rondelet (1554), Gesner (1558), and
Aldrovandi (1613 and 1640). Some of these figures show the influence of
mythological ideas, but were undoubtedly based on such malformed rays
as are figured above. Such no doubt is that shown in figure 5, though it
has plainly been manipulated by hand and dried to form the monster
as portrayed by Aldrovandi. I have seen present-day manipulations
produce comparable apparitions. Some day I hope to bring a large
number of these figures together, as an interesting chapter in the history
of 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-

= ~~
7 “Dy, WS

SiS

LY).

el
5 RY
SS ey

T==

Fig. 5. The priestfish. A malformed, hand-manipulated, dried ray with which
the artist took many liberties in his drawing.
i After Aldrovandi, 1613.

lated 35 in my file marked “‘ Malformed Rays.”’ Close search through the
literature will undoubtedly bring others to light. I hope some time to
bring together all these modern accounts with their interesting figures
in an article covering the field thoroughly. To do so now is beyond the
purpose of this short article. However, it may not be out of place to give
three 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 an
account of such a ray taken on the coast of Sicily and described in 1810
by that strange genius, Constantine Rafinesque-Schmaltz.1 He thought
it was a distinct genus and gave its characters as follows (free transla-

tRafinesque-Schmaltz, C.S. 1810. ‘Indice d’Ittiologia Siliciana.’ Messina. (Cephaleuthurus, p.61.)

1933] AN ABNORMAL FORM OF RAJA STABULIFORIS 7

tion): ‘Head free and separated from the lateral wings; eye and spiracles
united [near to each other] and situated on the side of the head; two
fins above the tail, none at the extremity.” Then he adds: ‘This genus
is 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

Fig. 6. Propterygia hypostica, a so-called new genus and species of ray. Here a
second split has divided each pectoral fin into an anterior horn and a posterior fin.
After Otto, 1821.

8 AMERICAN MUSEUM NOVITATES [No. 600

wings [fins].’”’ He names his form Cephaleutherus maculatus, and notes
that 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 in
- 1818 obtained from a fisherman at Edinburgh one of the most greatly
malformed rays ever figured and described. As may be seen in figure 6,
this differs markedly from our two Woods Hole specimens. First there is
the normal split between the head and pectorals; then in some way not
clear the fins have become split again to form two forward-pointing
anterior horns and the two lateral wings. Otto also thought that he had
a new genus and species, which he named Propterygia hypostica. His fish

Fig. 7. Hieroptera abredonensis, the Aberdeen priestfish. It has the same type
of abnormality as that found in the Woods Hole specimens.
After Fleming, 1841.

was small—18 inches long (equally divided between body and tail) and
13 inches wide. His figure was evidently made after the specimen had
become dried.

The next specimen to be figured and described (so far as I can find
out) dates twenty years;forward. In 1841, Flemming? described, also
from Scottish waters, a teratological ray which he thought was a new
genus and species, and which he called Heiroptera abredonensis (the
priest-winged fish from Aberdeen). This is shown as figure 7 herein. It
is very like the two Woods Hole fish, and needs no further description.

10tto, A. W. 1821. ‘Ueber eine neue Roche (Propterygia hypostica),’ etc. Nova Acta Acad. Leo-
poldino-Carolinez, X, pp. 113-121, 2 plates. . ;

2Flemming, John. 1841, ‘Description of a Species of Ray New to the British Fauna.’ Edinburgh
New Philos. Journ., XXXI, pp. 236-238, 2 plates.

1933] AN ABNORMAL FORM OF RAJA STABULIFORIS 9

From this time on, the literature becomes too voluminous and com-
plex to be covered satisfactorily in this short article. It is my intention
later to collect and present it in definite form with all the interesting
figures to show how, only after a period of 75 years, the matter was
thoroughly cleared up—by Theodore Gill in 1896.

How Tuis ConpITION Comes ABOUT

The explanation is to be found in the embryology of the skate. The
skates and rays are highly specialized forms of the great group Elasmo-
branchii—forms which have evolved beyond the sharks by developing
modifications for bottom-living. To this end the round body of the
shark has become flattened, the pectorals have become enormously en-

Fig. 8. The angel shark, Rhina squatina, an intermediate form between shark
and ray. Note the permanent notch between pectorals and head.
After Boulenger, 1904.

larged and have become adherent to the neck and head region. In this
process, the gill-openings have been forced from a lateral to a ventral
position. 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 yet
adherent 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 Woods
Hole.

10 AMERICAN MUSEUM NOVITATES [No. 600

This matter will be made clearer by study of figure 9, which was
drawn from the larval form of the sting-ray, Dasyatis say. This baby
ray I cut from the uterus of the mother at Beaufort, JN. C., many years
ago. In this Cesarean 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 complete
sets of stages for other rays, and have personally found, what is of course
well known, that in its development the baby ray “climbs its own

Fig. 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 grown
fast 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 a
ray, passing through the stages shown in figures 9 and 8. From this it is
clear that the specimens of the barn-door skate described herein are
cases of arrested development, of fixed larval forms, directly comparable
to the perennibranchiate urodeles among amphibians.