Type material
provided by Echinoderms of Panama
Type material: ST: MCZ 8396-8397, 9398, USNM E11376-E11378.
Type locality: Pillsbury Stat. 402 (8°51'N, 77°02'W, off northern Columbia, depth 73 m), Pillsbury Stat. 399 (9°01'N, 76°39'W, off northern Columbia, depth 147 m); White Shoal, Dry Tortugas, Florida; RHCK 45, off Aligator Reef, Florida Keys; Gerda Stat. 683 (25°52'N, 77°53,5'W, Northwest Providence Channel, Bahama Islands, depth 250 m).
Comprehensive Description
provided by Smithsonian Contributions to Zoology
Paraster doederleini Chesher
Paraster doederleini Chesher, 1972a:10–25, figs. 1–9.
The Carrie Bow specimens are indistinguishable fiom the Floridian holotype of this species that previously was reported only from Florida and Colombia. Chesher (1972a:21) noted that the Colombian specimens were slightly different from the Floridian specimens and postulated that the “differences between the two populations are not significant and will probably prove to be part of a morphological cline when more specimens are found.” However, two of Chesher’s Floridian paratypes are similar to the Colombian specimens. This suggests that a morphological cline based on geographic separation probably does not occur between the Floridian and Colombian populations. The Carrie Bow Cay specimens are indistinguishable from the holotype and two of the paratypes but readily differentiated both statistically and by visual inspection from the Colombian specimens and two of the Floridian paratypes. The fact that no intermediates between these two groups are present either among Chesher’s types or among the Carrie Bow Cay specimens and that the two have never been found living together suggests that these groups should probably be differentiated taxonomically. However, until we know more of the geographic distribution of the two groups and the variation within the “Colombian population” it seems best to postpone any taxonomic decision.
Group I -- Carrie Bow Cay specimens (25) plus Chesher’s E11376, 8397C, and 8397D. All these specimens have straight posterior petals.
Group II -- Chesher’s E11378, E11377, 8398, 8396B+, 8396B, and 8396A. All these specimens have curved posterior petals.
*Because of few specimens in Group II, variance so high as to indicate in f-test that t-test may not be valid. However, there is no overlap between means in Group I and II (min-max) and differences appear to be very significant — see scattergrams for AP and APE.
The two groups are easily distinguished visually by the straight posterior petals and longer anterior petals found in the Carrie Bow Cay specimens, the holotype, and paratypes USNM El 1376, MCZ 8397c, and MCZ 8397d (these specimens henceforth are referred to as group i). The specimens in group II (the Colombian paratypes and the Floridian paratypes, USNM E1 1378 and MCZ 8398) have flexuous posterior petals and much shorter anterior petals. These differences are readily apparent when one compares the photographs of specimens equivalent in size in both groups on Plate 7: figures 3 (group I) and 6 (group II).
Statistically, specimens in group I differ from group II in having longer and wider anterior and posterior paired petals with a greater span and more pore-pairs. They have a wider ambulacrum III, larger periproct, and a greater distance between the apical system and the peripetalous fasciole as measured along the center of ambulacrum III and interambulacrum 4. The peristome is more posterior; the anterior notch, deeper and wider; the peripetalous fasciole, longer; and the test, slightly wider. The statistics of these characters for the two groups together with the results of t-tests of the significance of the differences are presented on Table 1. The difference between the two groups in the span and length of the anterior petals is shown graphically in Figure 7.
Although the groups are easily differentiated, the taxonomic separation is probably not as great as might seem. Specimens of both groups have their fascioles crossing the same plates in each ambulacrum and interambulacrum, a feature which Chesher has proved to be of great significance.
Because Chesher’s description and statistics are based on specimens of both groups, I am including a description and statistics of 25 specimens from a single population from Carrie Bow Cay and the measurements (Table 2) of the holotype.
MATERIAL.—Statistics from 25 specimens collected at same locality.
SIZE AND SHAPE.—Specimens 14.7–51.9 mm long, mean 35.49 mm, width 96.47 percent TL (SD 1.72, CV 1.8), height 73.78 percent TL (SD 3.10, CV 4.2); posterior truncated obliquely, dorsally overhanging so that periproct visible adorally; greatest width of test anterior at anterior series of interambulacra 1 and 4; greatest height posterior at interambulacrum 5 between posterior petals.
APICAL SYSTEM.—Posterior of center, distance from anterior margin 52.86 percent of TL (SD 2.39, CV 4.5); ethmolytic, tetrabasal (Figure 8B) with four genital pores, anterior pair about one-third diameter of posterior pair; posterior pair present on all specimens including smallest 14.7 mm long, anterior pair absent on smaller specimens 14.7 and 17.7 mm long, present on next larger specimen 20.2 mm long and all other specimens; 14 specimens with plate sutures of apical system visible, 13 tetrabasal, one specimen tribasal with genital 1 missing (Figure 8B), 10 specimens with genital 2 extending posteriorly joining ocular v and separating genital 4 from genital 2 (Figure 8B), one specimen with genital 3 extending posteriorly into interambulacrum 5 instead of genital 2.
AMBULACRA.—Anterior ambulacrum III in sunken furrow extending from apical system to peristome forming pronounced notch in front of test with depth 4.61 percent TL (SD 2.36, CV 51.1), width 20.23 TL (SD 2.15, CV 10.6), slightly sunken at edge of peristome; pore-pairs in single series, not conjugate, pronounced node separating pores of pair; pores situated parallel to plates but due to curvature of plates outer pore of pair slightly posterior to inner; greatest width of ambulacrum m 14.92 percent TL (SD 2.22, CV 13.9); peripetalous fasciole crosses ambulacrum in at distance from center of apical system equal to 52.96 percent TL (SD 1.64, CV 3.1); ambulacral plates beyond peripetalous fasciole with single pore in each plate.
Anterior petals (II and IV) slightly flexuous, length 35.36 percent TL (SD 1.03, CV 2.9), greatest width 12.01 percent TL (SD 0.98, CV 8.1), ends of anterior petals separated apart distance equal to 58.34 percent TL (SD 1.74, CV 3.0). Posterior petals (V, L) straight, short, length 16.60 percent TL (SD 1.58, CV 9.5), greatest width 9.19 percent TL (SD 0.61, CV 6.6), ends of petals separated by a distance equal to 26.30 percent TL (SD 1.11, CV 4.2).
INTERAMBULACRA.—In smaller specimen, 17.7 mm long, 10 plates in interambulacrum 3a, 8 in 4a, 13 in 5a; few plates added during growth with only 12 plates in interambulacrum 3a in specimen 30.5 mm long, 9 in interambulacrum 4a, 13 in 5a. Interambulacrum 2b and 3a separated from ocular III in specimen only 19.6 mm long indicating that production of new plates had ceased in these interambulacra (Kier, 1956).
PERISTOME.—Anterior, distance from anterior edge of peristome to anterior margin of test 19.87 percent TL (SD 1.39, CV 7.0); not sunken; width 16.66 percent TL (SD 1.74, CV 10.4), height 4.26 percent TL (SD 0.94, CV 15.2). Labrum well developed, short, length 11.26 percent TL (SD 1.22, CV 10.8), extending back to posterior portion of first adjoining ambulacral plate or anterior portion of second (Figure 8A); distance from anterior tip of labrum to posterior of test 76.05 percent TL (SD 2.13, CV 2.8); 33 or 34 oral tubefeet arising from single pores, on some larger specimen large ridge rising alongside pore or crossing pore dividing pore in two.
PLASTRON.—Length 47.58 percent TL (SD 1.98, CV 4.2), width at junction of second and third adjacent ambulacral plates 25.29 percent TL (SD 1.99, CV 7.9), width at junction of third and fourth adjacent ambulacral plates 36.09 percent TL (SD 1.70, CV 4.7), width at junction of fourth and fifth adjacent ambulacral plates 38.23 percent TL (SD 1.60, CV 4.2).
PERIPROCT.—Small, ovoid, height 14.91 percent TL (SD 1.78, CV 11.9), width 9.81 percent TL (SD 1.23, CV 12.5), situated near middle or slightly above midpoint on posterior.
FASCIOLES.—Peripetalous fasciole curving slightly towards apical system in interambulacra 2, 3, more deeply in interambulacra 4 and 1; straight across interambulacrum 5; greatest width where passing around petals II and IV; distance from apical system to posterior portion 18.28 percent TL (SD 0.91, CV 5.0), to lateral portion (along center of interambulacrum 4) 16.87 percent TL (SD 0.86, CV 5.1); length of fasciole 203.42 percent TL (SD 6.17, CV 3.0); Lateroanal fasciole passes below anus, at distance from lower portion of anus slightly greater than height of anus; length of fasciole 170.45 percent TL (SD 4.31, CV 2.5).
See Chesher (1972:20) for plates on which fascioles occur.
PEDICELLARIAE.—Tridentate common, largest occurring near peristome with stalks 2 mm long, valves 1.2 mm long (Plate 7: figures 10, 11); rostrate (Plate 7: figures 12–14) less common with stalk 1.3 mm long, valves 0.75 mm long, seen on periproctal plates, in apical region near edge of petals; globiferous (Plate 7: figures 7–9) rare, with a circle of small spines surrounding the terminal opening.
ECOLOGY.—This species occurs in large numbers buried in mud fields west and south of Water Cay Range. The water depth is between 12 and 18 meters. These mud fields can be identified from the surface on a clear day by the azure-blue color of the water. The mud fields are white, with worm mounds and the algae Penicillus and Udotea conglutinata (Ellis and Solander). The echinoids live buried 20–100 mm below the surface. I could see no evidence of their presence at the surface. Their density varied from locality to locality but was greatest in the finer sediments, decreasing where the sediment contained some silt or sand. Maximum density was approximately one to two specimens every square meter. The echinoids are light yellowish tan with bright red tubefeet in the anterior ambulacrum (III) and orange tubefeet in the phyllodes. They bury beneath the surface in approximately 15 minutes (Plate 8: figures 1–3). Three other spatangoids are present with them: Brissopsis elongata Mortensen, Moira atropos (Lamarck) and Paraster cf. Paraster floridiensis (Kier and Grant). Paraster doederleini occurs in far greater numbers than any of these species. In 20 minutes of collecting, 30 specimens were found of P. doederleini, six of M. atropos, one of B. elongata, and none of P. cf. P. floridiensis.
Paraster cf. Paraster floridiensis (Kier and Grant)
Schizaster (Paraster) floridiensis Kier and Grant, 1965:50–54, fig. 15, pi. 13: figs. 4–6; pi. 14: figs. 1–9.—Kier, 1966:9.
Paraster floridiensis.—Chesher, 1966:1–19, figs. 1–6, tables 1–2; 1972a, tables 1, 2.
In 1973 we collected in the same mud field with Paraster doederleini, Moira atropos, and Brissopsis elongata, one specimen of a small spatangoid very similar to Paraster floridiensis. When we returned to the same site in 1974, we were determined to find more specimens. After 11 dives and approximately 7 hours of searching, we located only one more. Because of the scarcity of the specimens, we thought that perhaps we were on the fringe of a larger population present in adjacent areas. Extensive searching within two to three miles of the site revealed no more specimens.
These specimens may be conspecific with Paraster floridiensis; but until more specimens are found, their reference to this species must be tentative. They may represent a new subspecies. They are similar in most of their dimensions (Table 2) to specimens from Florida referred to P. floridiensis by Kier and Grant, and Chesher. Their peripetalous fasciole and Iateroanal fascioles also cross the same plates as in the Floridian specimens. They differ in that their tests are narrower, 86.90–88.52 percent of their total length as opposed to 91.08–95.59 percent of the total length in two Floridian specimens of approximately the same length (Chesher, 1972a: 19, reports a mean of 92.66 for all the specimens he measured). The anterior paired petals in the Carrie Bow Cay specimens are straighter than in P. floridiensis. This difference is readily seen in a comparison of photographs (Plate 10) of the Carrie Bow Cay specimens and a specimen referred to P. floridiensis by Chesher (1966) of approximately the same size. The anterior petals in the Carrie Bow Cay specimens curve more anteriorly; whereas they curve more posteriorly in Chesher’s specimen. Finally, the tridentate pedicellariae in the Carrie Bow Cay specimens (Plate 10: figures 10, 11) differ in having longer, better defined serrated heads than those figured by Chesher for P. floridiensis.
The Carrie Bow Cay specimens strongly resemble P. rotundatus Döederlein from the Galapagos. Their anterior petals are similar, not flexuous, as in P. floridiensis; but their tests are narrower and their anus larger. The tridentate pedicellariae in the Carrie Bow Cay specimens are intermediate in shape between those found in P. floridiensis and P. rotundatus, having their heads longer with better defined serrated heads than in P. floridiensis but shorter than in P. rotundatus.
Until more specimens have been found from Carrie Bow Cay, and of P. rotundatus from the Galapagos, it is impossible to know the significance of the differences between the Carrie Bow Cay specimens, P. floridiensis and P. rotundatus. At first glance I thought that the differences between the Carrie Bow Cay specimens and the Floridian specimens of P. floridiensis and the similarity shared by the Carrie Bow specimens and the Galapagos species suggested that the Carrie Bow Cay specimens were more similar to the Pacific species because of their nearer geographic location. However, a specimen of P. floridiensis recently collected by Dr. David Meyer from the San Bias Islands off the Republic of Panama (USNM El3753) is indistinguishable in the width of its test and flexuous petals from the Florida specimens, even though it occurs nearer to the Galapagos Islands than the Carrie Bow Cay specimens. Perhaps, as suggested by Chesher (1972b: 149) the Pacific counterparts of the Atlantic species exist but remain to be found.
LOCALITY.—The two specimens were buried 10–15 mm beneath and surface at a depth of 15 m in mud fields west and south of Water Cay Range. Chesher (pers. comm., 1974) points out that his Floridian specimens were all found in coarse sand.
- bibliographic citation
- Kier, Porter M. 1975. "The echinoids of Carrie Bow Cay, Belize." Smithsonian Contributions to Zoology. 1-45. https://doi.org/10.5479/si.00810282.206
