CTENANTEDON, A NEW ANTEDONID CONVERGENT WITH COMASTERIDS

DAVID L. MEYERl Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, D. C. 20560

ABSTRACT A new genus and species of comatulid crinoid, Ctenantedon kinziei, is described from Cura9ao and Santa Marta, Colombia. It is placed within the suborder Macrophreata, family Antedonidae, subfamily Antedoninae. In the well-developed comb teeth on the oral pinnules and the radial arrangement of the distal pinnules, C. kinziei resembles certain species of Nemaster (suborder Oligophreata, family Comasteridae) which cooccur with C. kinziei. Since the living habits of C. kinziei also resemble those of the sympatric species of Nemaster, the morphologic resemblance is con- sidered to represent convergent adaptation to similar modes of life.

INTRODUCTION In the course of a recent investigation of the ecology and functional morphology of shallow-water unstalked (Echinodermata) of the Caribbean Sea (Meyer, 1971), I have discovered a new and unusual comatulid crinoid from Curac;ao and Colombia. It is described herein as Ctenantedon kinziei, new genus and species, and is placed within the family Antedonidae, subfamily Antedoninae. While it is most closely related to the antedonids, the new species shows some features found in the family Comasteridae, especially the development of comb teeth on the oral pin- nules. In Colombia, Ctenantedon kinziei was found living in close sympatry with four species of coma sterid comatulids (Nemaster grandis Clark, N. rubiginosa [Pourtales], N. discoidea [Po H. Carpenter], and Comactinia echinoptera [J. MUller]), and one tropiometrid comatulid (Tropiometra carinata carinata [Lamarck]). Similarities in the living habits of C. kinziei and some of the cooccurring comasterids suggest that the morphologic resemblance of C. kinziei to comasterids represents convergent adaptation. Terminology used in the following descriptions is generally that of A. H. Clark (1915: 59-114).

Ctenantedon, new genus Diagnosis.-A genus of Antedoninae in which the first four (sometimes the first two or three) pinnules are modified to become oral pinnules. The oral pinnules possess conspicuous terminal comb teeth. The fourth pinnule

1 Present address: Smithsonian Tropical Research Institute, P. O. Box 2072, Balboa, Canal Zone. 54 Bulletin of Marine Science [22(1)

cs FIGURE 1. Ctenantedon kinziei Meyer, n. gen., n. sp.: a, centrodorsal, aboral view of holotype (scale = 1 mm); b, oral view of same. (CS, cirrus socket; CC, central cavity; L, lip.) is about twice the length of the first two, which are about equal in length. There are L-XCII cirri, each formed of 12-14 mostly elongate segments. The distal end of an individual cirrus segment only slightly overlaps the proximal end of the following segment. The name Ctenantedon is derived from the Greek kteis, ktenos, a comb, and , referring to the subfamilial designation. Type-Species.-Ctenantedon kinziei Meyer, new species, herein designated. Ctenantedon kinziei, new species Description of Holotype.--CENTRODORSAL (Fig. 1, a, b): The centrodorsal has a shallow, bowllike shape (diameter: 4.4 mm; height: 1.1 mm). Its oral surface is slightly concave, with five interradial grooved ridges which do not reach the centrodorsal margins. The radial areas of the oral surface have radiating furrows. The presence of a conspicuous overhanging lip makes the opening of the central cavity small (diameter: 0.9 mm), although the cavity itself is moderately deep and broad. The lip of the central cavity is raised and has five radial and five interradial scallops. The cirrus sockets are crowded over most of the aboral surface of the centrodorsal except for a bare polar area (diameter: 1.4 mm). The cirrus sockets are arranged in alternate rows or irregularly. The sockets are tear- drop-shaped, with the narrow end pointed aborally, and are deeply set into the centro dorsal surface. CIRRI (Fig. 3,h): There are XCII cirri, each formed of 12-13 segments. The maximum length of a mature cirrus is 17 mm. The first segment is very short, the second about three times as long as the first, the third slightly 1972] Meyer: Ctenantedon, a New Antedonid Crinoid 55

AMB \

BR IlF c RNC

FIGURE2. Ctenantedon kinziei Meyer, n. gen., n. sp.: a, radial pentagon, oral view of holotype (scale = 1 mm); b, aboral view of same; c, radial facet, lateral view of holotype (scale = 1 mm). (CC, central cavity; BR, basal rays; R, rosette; MF, muscle fossa; ILF, interarticular ligament fossa; DLF, dorsalliga- ment fossa; TR, transverse ridge; RNC, radial nerve canal; AMB, position of ambulacrum.) longer, and so on until about the seventh, beyond which the segments decrease in length, but never become shorter than their width. The length- to-width ratio of the longest segment is 4.2: 1. The longest segments are slender, with slightly expanded ends, the distal end slightly overlapping the proximal end of the next segment. The segments lack all spines or nodes, with the exception of the last two, which bear the terminal claw and opposing spine. The claw is larger than the opposing spine, and the opposing spine is either inclined slightly toward the claw or at right angles to its segment. RADIALS (Fig. 2, a, c): The radial pentagon does not cover the entire oral surface of the centrodorsal (diameter: 3.0 mm). This may be a juvenile condition. The faces of the radials are curved inward. The muscular fossae of the radials are very well developed, being tall and broad and larger than the interarticular ligament fossae. The muscle fossae curve sharply inward, so that there is no thick, wedge-shaped area between adjacent radials. The dorsal ligament fossa is low and almost truncated on the abambulacral side. 56 Bulletin of Marine Science [22(1)

A

"'Ut- ~]

1

c u 1972] Meyer: Ctenantedon, a New Antedonid Crinoid 57 The overall appearance of the radials is very similar to those of Hath- rometra tenella (Retzius) and Thaumatometra tenuis (Clark) (subfamily Bathymetrinae) (see Clark, 1921: 67, figs. 102-105, 108-109). In C. kinziei, the faces of the radials are more concave than in these species. BASALS(Fig. 2, b): The basal rosette is located slightly above the proxi- mal surface of the radial pentagon. It has a simple pentagonal shape, with the triangular radial processes turned downward to join the scalloped lip of the central cavity of the radial pentagon. The interradial processes are weakly developed and turned upward; they are not at all "spoutlike." This rosette is similar in proximal view to that of Coccometra hageni (Pourtales) (see Clark, 1915: 369, fig. 499). The basal rays are strongly developed, projecting from between adjacent radials. A suture is visible between adjacent basal rays along the interradial lines. Since Clark (1915: 329) has stated that the basal rays are of very uncertain systematic value, no particular significance is attached to their development in this species. The central cavity of the radial pentagon is bordered by a lip having five narrow radial scallops and five broad interradial scallops which cor- respond to those of the lip of the centrodorsal cavity. RAYS (Fig. 4): There are ten arms, each measuring about 100 mm from centrodorsal to tip. (This figure is based on the paratype, since the holotype autotomized badly. The holotype is of about the same size.) Following the conventions adopted by A. M. Clark (Clark & Clark, 1967: xii) for recording the size of comatulids, the length in the holotype from the beginning of the ray (proximal edge of first primibrach) to the second syzygy is about 9 mm, and the arm width at the first syzygy is about 1.5 mm (both measured on C ray). The first primibrach is short, with its proximal side curved and its distal side straight. The second primibrach is the axillary (plate on which ray divides); it is triangular and short. The first brachial (Brd is a short wedge; Br~ a thick wedge bearing the first pinnule (Pd; BrrS+4 the first syzygial pair, together parallelogram-shaped; Br5 through Brnor10 wedge- shaped or rectangular. Those brachials following Brnor12 are triangular, becoming more elongate distally. The distal edges of the brachials are slightly spinous. Syzygies are located between brachials 3 + 4, 9 + 10 or 10 + 11, 14 + 15 or 15 + 16, 18 + 19,23 + 24, 27 + 28,32 + 33, and so on, at intervals of three or four brachials. PINNULES(Figs. 3, a-g; 4; 5, a): Ph on Brz, is about 6.0 mm long, with 21-25 segments. Segments 1 and 2 are broader than the rest, and segments 3-6 may have sharp angles at their distal ends on the abambulacral side. The middle segments are elongate. The distal 5-8 segments (except the last 2 or 3) each bear a flat tooth, which is usually double. Pz, on Brj, is about 7.0 mm long, with 22-26 segments. The distal 7-10 58 Bulletin of Marine Science (22(1)

FIGURE 4. Arm and pinnules of Ctenantedon kinziei Meyer, n. gen., n. sp., paratype. Photographed alive in aquarium. Note spotted color pattern of arms, great length of pinnules and their four-row arrangement along arm, and rows of tube feet extended along pinnules. (Scale = 1 mm.) 1972] Meyer: Ctenantedon, a New Antedonid Crinoid 59 segments (except the last 2 or 3) each bear a tooth similar to those of Pl' Other features are as in Pl' P3, on Br7, is about 10 mm long, with 25-30 segments. The distal 9-13 segments (except the last 2 or 3) each bear a tooth similar to those of Pl' Other features are as in Pl' P4, on Bro, is about 14 mm long, with 29-37 segments. The distal 9-14 segments (except the last 2 or 3) each bear a tooth similar to those of Pl' The proximal segments lack sharp angles.

p.;, on Brl2, is much shorter than P4, with 16-27 segments. Comb teeth are lacking except in one case where there were five poorly developed teeth. The pinnules on the inner side of the arm are similar to the outer pin- nules, except that usually only the first three have comb teeth, and the fourth pinnule is shorter than the third. Beyond the oral pinnules, the pinnules gradually increase in length until they almost exceed the length of the longest oral pinnule (about 14 mm). There are about 28 elongate segments, each with expanded ends, the distal ends spinous. Abundant sacculi line the ambulacra. The most significant feature of the distal pinnules, in addition to their great length, is the manner in which they are oriented with respect to the arm. In life, the pinnules of an arm are aligned in four rows instead of two (Fig. 4). Along each side of the ambulacrum, the pinnules are pointed alternately toward the ambulacral (ventral) side and the abambulacral (dorsal) side, producing two rows of pinnules on each side of the am- bulacrum of an arm. This radial configuration is found in some comasterid species as well (Nemaster rubiginosa and N. discoidea). In this species the four-row arrangement is not easily seen in preserved specimens. DISK: The mouth is nearly central, the anal tube submarginal. The anal tube is nodose. COLOR IN LIFE: The arms are light brown. A very conspicuous feature is the presence of a black spot at each end of the hinges articulating adjoin- ing brachials (Fig. 4). The pinnules are banded brown and white. The ambulacral areas of the arms are speckled with black, and the sacculi lining thc brachial and pinnular ambulacra are brown.

Description of Paratype.-The second Colombian specimen, designated the paratype, has been preserved whole, without detailed dissection. Examina- tion shows that it is very similar to the holotype in all respects. One dif- ference is that usually only the first three pinnules of an arm are modified into oral pinnules bearing comb teeth. P3 is usually the longest oral pinnule, with p 4 shorter and lacking comb teeth. Some arms did have the first four pinnules modified, as in the holotype. Another difference is that the second brachial syzygy is located between either Brrs + 0 or Brrlo + 11. This specimen has only LXX cirri. 60 Bulletin of Marine Science [22(1) Description of Cura{:ao Specimen.-Unfortunately, this specimen was de- voured by a small fish in my aquarium before I was able to preserve it. Only cursory observations are available, but it was certainly conspecific with the Colombian specimens. It was probably a juvenile, with arm length of only about 30 mm. There were L-LX cirri; and only the first two pinnules had comb teeth. In contrast to the two Colombian specimens, the anal tube was central and tall, covered with tubercles. The radial pin- nular pattern was not observed, although other external features, color pattern, and mode of swimming were similar to those of the Colombian specimens. Occurrence.-The two Colombian specimens were collected by SCUBA diving at Punta Betin, just below the Instituto Colombo-Aleman, at Santa Marta, Colombia. Both specimens were attached to the undersides of corals along a reef slope that runs from Punta Betin to Morrito Rock, at a depth of about 18 meters. One specimen was partly visible; the other was entirely concealed from view until the coral slab was overturned. The single Curat;ao specimen was collected by SCUBA diving at Cor- nelisbaai, on the southwestern coast of Cura9ao. It was attached to a coral slab at a depth of about 36 meters. Locomotion.-When disturbed, all three specimens swam vigorously in the manner typical of swimming comatulids. Every other arm was raised orally at the same time the other five arms were lashed aborally, producing movement in the oral direction. When preparing to settle down onto the substratum, the swimming C. kinziei employed another mode of swimming. The arms were flexed orally all at once, resulting in a jerky progression in the aboral direction, which ceased abruptly when the cirri grasped the substratum. To my knowledge, this latter mode of comatulid swimming has never before been recorded. It is not known how any of these swimming movements enter into the natural life history of the . I am pleased to name this species in honor of Dr. Robert A. Kinzie, III, who found the first specimen while diving with me in Curat;ao. The type-material is deposited in the Division of , National Museum of Natural History, Smithsonian Institution, Washington, D. C. Systematic Position.-All previously described comatulids having well- developed comb teeth on the oral pinnules have been placed in the family Comasteridae of the suborder Oligophreata. Thus, the presence of such combs in C. kinziei at first led me to consider it as a comasterid. Detailed examination, however, shows that the new comatulid possesses many characters which preclude its placement with the Oligophreata. According to A. H. Clark (1915: 75), the primary feature of the Oligophreata is that "the cavity in the centrodorsal containing the cham- bered organ and overlying structures is very small and shallow." In C. 1972] Meyer: Ctenantedon, a New Antedonid Crinoid 61 kinziei the ratio of central cavity diameter to centrodorsal diameter is rather small (1:4.9), although the cavity is moderately deep (Fig. 1,b). Examination of Clark's (1915) figures 229-297 shows that there is considerable variation in this ratio within each of the two suborders Oligophreata and Macrophreata. Among eleven oligophreate genera, the ratio ranged from 1:2.4 to 1:5.6; and among five macrophreate genera from 1: 1.5 to 1:4.3. The considerable overlap in these ranges makes it very difficult to know where to draw the line between these two suborders on this one character. Although C. kinziei seems to fall closer to the Oligophreata on this character, examination of other features indicates closer affinity to the Macrophreata. First, the opening of the central cavity is partly covered by an over- hanging lip (Fig. 1,b), a feature considered by Clark to be more charac- teristic of the Macrophreata (1915: 234). Thus the diameter of the cavity is actually greater than appears superficially. Note, in Figure 1,b, that part of this lip has been broken away at the 11 o'clock position. This indicates the actual maximum width of the cavity, which produces a ratio even closer to the range of the macrophreates. The form of the radial pentagon of C. kinziei shows many similarities to those of the Macrophreata. The well-developed muscular articulations of the radials (Fig. 2, a, c) are strikingly different from those of comasterids and most other oligophreates (see Clark, 1921: figs. 1-75). As a con- sequence of the great size and concavity of the muscle fossae of the radials, the central cavity between the five radials is very narrow (Fig. 2, a). This condition contrasts sharply with that in most oligophreate forms, which have a broad, pentagonal, funnellike space between the radials filled with coarse calcareous stereom (see Clark, 1921: figs. 1-75). The radial facets slope in toward the central axis of the animal much more than in most oligophreates, where the radial facets nearly parallel the central axis. All these characteristics of the radials of C. kinziei combine to make them much more similar to typical macrophreate radials, which almost always have well-developed muscle fossae (see Clark, 1921: figs. 78-115). On these characters, C. kinziei especially resembles Hathrometra Clark, and Thaumatometra Gark (see Clark, 1921: figs. 102-105, 108-111). There are additional characters which indicate the closer relationship of C. kinziei to the Macrophreata than to the Oligophreata. The basal rosette of C. kinziei (Fig. 2, b) is macrophreate in lacking interradial "spoutlike" processes (Clark & Clark, 1967: 38). The cylindrical nature of the pinnule segments is also a macrophreate character present in C. kinziei (Clark & Clark, 1967: 38). The location of the second brachial syzygy in C. kinziei also suggests affinity to the Macrophreata, although variation in this character renders its interpretation somewhat equivocal. In the holotype and paratype of C. kinziei, the location of the second syzygy was found to vary, occurring 62 Bulletin of Marine Science [22(1)

between Brrs + 0, Brro + 10, or Brrlo + n. According to Clark & Clark (1967: 38), the second syzygy is usually between Brro + 10 in the family Antedonidae of the Macrophreata. Thus, C. kinziei falls very close to the Antedonidae in this respect. It should be noted, however, that some oligophreate genera of the family Comasteridae (such as Comatonia Clark, and Microcomatula Clark) have the second syzygy within the range of variation observed in C. kinziei. The central location of the mouth in C. kinziei is a character more typical of macrophreate genera than of the comasterid genera of the Oligophreata, which C. kinziei resembles on the basis of its comb teeth. Nevertheless there are some comasterid oligophreates which do possess a central mouth (e.g., Comatonia, Comatilia Clark, and others mentioned by Clark [1921: 305]). Furthermore, the presence of sacculi lining the ambulacra of C. kinziei indicates a more likely relationship to the Macrophreata. Clark (1921: 352) noted that sacculi "are of more uniform occurrence in the Macrophreata than in the Oligophreata. They appear to be absent from the species of the family Comasteridae, excepting only Comatonia cristata." In classifying C. kinziei with the Macrophreata, I have placed emphasis on as many characters as possible, rather than relying on the single character of centrodorsal cavity size, which Ailsa M. Clark of the British Museum (N. H.) has indicated to me "is not absolutely diagnostic" (personal com- munication) and which has also been shown above to be inconclusive. Ctenantedon kinziei is easily classified as an antedonid macrophreate by using the key provided by Clark & Clark (1967: 39). The other two macrophreate families possess specialized characters not found in C. kinziei. The new genus is assigned to the subfamily Antedoninae, since it possesses all the characters diagnostic of the subfamily (see Clark & Clark, 1967: 44). Ctenantedon is distinct from other genera of the Antedoninae in having up to four proximal pinnules modified both in length and in the development of comasteridlike comb teeth. According to Clark & Clark (1967: 47), one group of antedoninid genera has only the first two pinnules modified, while a second group has the first three pinnules modified. On the basis of proximal pinnule length, Ctenantedon is most similar to the second group. Of these, Toxometra Clark, Dorometra Clark, and Eumetra Clark, are most similar to Ctenantedon in having PI and P2 smaller than Pa. In several species of Toxometra, P4 is of about the same length as Pa, with PG shorter, so that this genus appears to be most closely related to Ctenan- tedon. Toxometra is known from the Philippines and northwest Australia.

FEATURES OF Ctenantedon CONVERGENT WITH COMASTERIDS The development of comb teeth on the oral pinnules is the chief charac- teristic of the oligophreate family Comasteridae. The nature of these teeth is highly variable, as indicated by Clark (1921: figs. 594-657). Less well- developed toothlike processes are found in several macrophreate genera of 1972] Meyer: Ctenantedon, a New Antedonid Crinoid 63

a

d~ b

FIGURE 5. a, distal end of P3 of Ctenantedon kinziei Meyer, n. gen., n. sp., holotype; b, distal end of PI of Clark, specimen in author's collection; c, distal end of Pt of Anthometra adriani (Bell), USNM E3079; d, distal end of oral pinnule of Nemaster discoidea (P. H. Carpenter), specimen in author's collection. Arrows point in distal direction. (Each scale = 1 mm.) the subfamily Heliometrinae: Florometra Clark (Fig. 5,b, this paper), Solanometra Clark, Anthometra Clark (Fig. 5, c, this paper; see also Giskn, 1924: fig. 342), P. H. Carpenter (see Gislen, 1924: fig. 343), and Heliometra Clark (see Clark, 1921: figs. 544-546; Gislen, 1924: fig. 341). One species of the subfamily Antedoninae, Anna- metra occidentalis (Clark), has, toward the tip of Pi, "a slight swelling on the middle of each segment so as to produce the effect of a rudimentary comb" (Clark & Clark, 1967: 92, fig. 6,b). Clark (1921: 144) described the rudimentary combs of the Helio- metrinae as blunt carinations which are quite different from the flattened, elongate teeth typical of Comasteridae (see Fig. 5, d, this paper). This description fits most of the above examples except perhaps for the toothlike processes of Anthometra adriani (Bell) (Fig. 5,c) which are somewhat comasteridlike. The doubly pronged comb teeth of C. kinziei are strikingly distinct from all of these rudimentary macrophreate teeth, although they are very similar to those of the comasterids Nemaster rubiginosa and N. discoidea (Fig. 5, d). Both species cooccur with C. kinziei. Aside from this similarity of the actual teeth, the oral pinnules of C. kinziei are very 64 Bulletin of Marine Science [22(1) different from those of Nemaster and other comasterids in the elongation of the middle segments (Fig. 3, a-d). In my opinion, the resemblance of the comb teeth of C. kinziei to those of comasterids is the result of secondary convergence, and does not indicate close primary phylogenetic relationship between Ctenantedon and the comasterid line. The presence of at least rudimentary comb teeth in several macrophreate genera shows that comb teeth are of polyphyletic origin. The comasteridlike comb teeth of Ctenantedon are considered here to represent an extreme case of convergence with comasterids in the antedonid line. It seems much more reasonable to assume that a character like the comb teeth could be independently derived, as opposed to the several macrophreate characters (especially those associated with the radials) noted earlier. In short, it seems much more reasonable to argue that Ctenantedon is an antedonid which has developed comasteridlike comb teeth than to claim that it is a comasterid which has independently evolved radials with highly developed muscular articulations presumably associated with the swimming ability, as well as other macrophreate characters. It is likely that some of the genera considered as comasterids by A. H. Clark (1931) should be classed with macrophreate subfamilies. Clark evidently placed heavy emphasis on the development of comb teeth. In Comatonia cristata (Hartlaub), the comb teeth are well developed (Clark, 1931: 291). However, the characteristics of the radials (which were not reported by Clark) are very different from typical comasterid radials. Examination by me of C. cristata (USNM 34628) showed that its radials have strongly developed muscle fossae not unlike those of Ctenantedon. Furthermore, the central cavity of the centrodorsal is very large and deep --clearly macrophreate. This species possesses a number of other macro- phreate characters mentioned earlier, which Clark noted, saying that it re- sembled some of the Antedonidae, but that its comasterid affinities were indicated by the comb teeth. It is noteworthy that Gislen (1924: footnote to p. 229) considered Comatonia a macrophreate, "possibly related to Heliometrinae." Thus there appears to be another case where a macro- phreate species independently evolved comasteridlike comb teeth. It is probable that the comb-bearing pinnules of C. kinziei perform a function similar to that of their comasterid counterparts, although insuffi- cient information is available on the activities of the oral pinnules in the new species. In the comasterids that I have observed, the function of the oral pinnules seems to be much like that of the echinoid pedicellariae. The oral pinnules have been observed to whip actively in and out from the disk, with the combs scraping across it. This action may serve to remove foreign particles, uningested food particles, feces, etc. The combs may also remove foreign growth from the cirri. Gislen (1924: 291) made the interesting suggestion that the comb-bearing pinnules of comasterids assist in feeding by placing particles dropped onto the disk into the food grooves or mouth, 1972] Meyer: Ctenantedon, a New Antedonid Crinoid 65 or by actually supplementing the suspension-feeding system by plucking off food particles within immediate reach. No observations are available on the action of the oral pinnules in C. kinziei. They are probably not as flexible as those of comasterids, since the individual segments of the middle portion are elongate. Furthermore, the first oral pinnules of C. kinziei are short, followed by two longer ones (Fig. 3, a-d). In Nemaster, the first oral pinnules are longest, followed by several shorter ones. How length of oral pinnules is related to their func- tioning in any of these species is not clear. The other feature in which C. kinziei appears to be convergent with comasterids is the arrangement of the distal pinnules, which, as described earlier, is a four-row, radial pattern. The same arrangement occurs in Nemaster rubigioosa and N. discoidea, which are sympatric with C. kinziei. I have suggested that the radial pattern represents an adaptation for suspen- sion feeding in a multidirectional (or turbulent) regime of water movements (Meyer, 1971). The two species of Nemaster are always found attached beneath corals so that only the arms extend; turbulent water movements prevail in this region of the reef. The three known specimens of C. kinziei were found living in a manner similar to the cooccurring species of Nemaster. It is probable that there is a common adaptive strategy among the genera Nemaster and Ctenantedon, which is to present extended arrays of tube feet in as many different direc- tions as possible where water flow is complex.

ACKNOWLEDGMENTS I thank the staffs of the Caribbean Marine Biological Institute, Cura<;ao, Dr. F. Creutzberg, former Director, and of the Instituto Colombo-Aleman de Investigaciones Cientificas, Santa Marta, Colombia, Dr. R. Kaufmann, Director, for their hospitality and help during my visits. I also thank my diving assistant, William K. Sacco, and my wife, Kaniaulono, who prepared the illustrations. This research was supported by a National Science Foun- dation Graduate Fellowship, The Geological Society of America, The Society of the Sigma Xi, Yale University Graduate School, and a Visiting Research Associateship at the Smithsonian Institution.

SUMARIO

Ctenantedon, UN NUEVO CRINOIDEO ANTED6NIDO CONVERGENTE CON COMASTERIDOS Se describe un nuevo genera y especie de crinoideo comatUlido, Cte- nantedon kinziei, procedente de Cura<;ao y Santa Marta, Colombia. Se situa dentro del Suborden Macrophreata, Familia Antedonidae, Subfamilia Antedoninae. Por los bien desarrollados dientes del peine de las pinnulas orales y el arreglo radial de las pinnulas distales, C. kinziei se parece a 66 Bulletin of Marine Science [22(1) ciertas especies de Nemaster (Suborden Oligophreata, Familia Comasteri- dae) que se presentan junto con C. kinziei. Como los habitos de vida de C. kinziei tambien se parecen a los de la especie simpatrica Nemaster, el parecido morfologico se considera que represent a adaptaciones conver- gentes a modos de vida similares.

LITERATURE CITED CLARK, A. H. 1915. A monograph of the existing crinoids. Bull. U. S. natn. Mus., No. 82, 1, Pt. 1,406 pp. 1921. Ibid., Pt. 2, 795 pp. 1931. Ibid., Pt. 3, 816 pp. CLARK, A. H. AND A. M. CLARK 1967. A monograph of the existing crinoids. Bull. U. S. natn. Mus., No. 82, 1, Pt. 5, 860 pp. GISLEN, T. 1924. Studies. Zool. Bidr. Upps., 9: 1-316. MEYER, D. L. 1971. Functional morphology and autecology of shallow-water unstalked crinoids (Echinodermata) of the Caribbean Sea. Unpublished Ph.D. dissertation, Yale University, 143 pp. (Available through University Microfilms, Ann Arbor, Michigan.)

NOTE ADDED IN GALLEYS: Since this paper went to press, C. kinziei has been found commonly at 10 m depth off Ucubsui, San BIas Islands, Republic of Panama, where individuals of this species emerge by night from daytime hiding places. The San Bias speci- mens are very similar in morphology and living habits to those described here.