Laevichlamys multisquamata (Dunker, 1864)
DUNKER, W. 1864. Fünf neue Mollusken. Malakozoologische Blatter, 11: 99-102. [p. 100]
Pecten multisquamata Dkr.; W. Dunker, 1858-1870, Novitates Conchologicae, Mollusca Marina, plate 23, figures 1-3.
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«Testa ovata, tenuis, paullo pellucida, valde compressa, obliqua, inaequivalvis, striis costulisque ab apice radiantibus numerosissimis eleganter confertimque imbricatis instructa, varie picta pallide fulva, fusco purpureoque variegata, ad apicem citrina, valva dextra interdum tota citrina; valva sinistra dextra paullulum convexior; auriculae valde inaequales striatae, auricula valvae dextrae major pro bysso emittendo late sinuata; sinus inferne denticulatus; latus conchae internum sulcis pluribus costulis externis respondentibus insigne, ceterum laevigatum, nitidum, pallide purpureum, albo luteoque variegatum; margo tenuiter sulcatus; fovea ligamenti parva. — Altit. testae 64, latit. 58, crass. 11 mill.
Habitat in sinu ad Habanam. Haec species pulcherrima ab amico J. Gundlach Dre detecta, tam habitu, quam striis numerosissimis squamulisque erectis totam testam occupantibus insignis est.» WILHELM DUNKER, 1864
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«Types.— The specimen illustrated by Dunker (1865), a pair of matching valves, is of the same dimensions given in his original description in 1864 and would be the logical
choice for a lectotype. It is not known, however, whether this specimen still exists. I did not find it among Dunker's material in the collections of the Humboldt University Museum of Berlin, raising the possibility that it may still be in Cuba, perhaps in the collection of J. Gundlach, from whom Dunker received his specimens. According to Dr. JosB Espinosa of the Instituto de Oceanologia of Cuba (pers. comm., 1993), however, no specimens of Pecten multisquamatus are present in that collection. A second, smaller pair of matching valves from Cuba that bears one of Dunker's manuscript names is housed with some of Dunker's collection in the Humboldt University Museum in Berlin. This specimen, a pair of matching valves collected by Felipe Poey from Cuba, is selected herein as the lectotype of P. multisquamatus. Its dimensions are height, 43.1 mm, length 39.5 mm, convexity of articulated valves 8.0 mm, length of anterior outer ligament 10.8 mm, and length of posterior outer ligament 5.0 mm. Dall (1886) provided no illustration with his original description of Pecten efluens but referred to the largest valve as having a height of 26.0 mm and a width of 22.0 mm. In the type collection of the National Museum of Natural History, the lot marked "types" (USNM 62236) contains a left valve and a smaller, non-matching right valve. The left valve, although conforming to Dall's description, is only half the size that he stated. Three years later Dall (1889, pl. 42, fig. 9) illustrated a Pecten efluens which he said had a height of 26 mm. This specimen, a left valve, corresponds exactly in shape and ribbing pattern to the left valve in USNM 62236 that is only half the size. It is assumed that Dall misstated the measurements from an enlarged drawing provided by an artist, and the left valve (ht. = 13.2 mm) in USNM 62236 is herein selected as the lectotype of P. efluens (Fig. 4h). Type locality.— Havana Bay, Cuba. Havana Bay, Cuba.
Diagnosis.— Laevichlamys of low convexity and streamlined, flaring form, the umbonal angle exceeding 90° for specimens greater than 20 mm in height; dorsal margin of right anterior auricle sharply folded and dorsal margin of right posterior auricle with slight trough; posterior margins of posterior auricles convex, producing distinctly oblique angle with hinge; ribbing retaining low relief throughout ontogeny, with all ribs and riblets having low, tiny, closely spaced scales.
Morphological variation.-- Laevichlamys multisquamata attains a moderate size, the largest specimens having a shell height of about 70 mm. The amplitude of the first-order radial plicae can vary considerably (compare Figs. 4b and 4f). The surfaces of some specimens are nearly flat, with only the fine costae present or with the first-order radial plicae limited to early ontogeny. The yellowish tinge on the umbones illustrated by Dunker (1865) and referred to by Dall (1886) is common but not present on all specimens
Comparison.— The morphology of Laevichlamys multisquamata is unique among chlamydoid scallops in the western Atlantic and eastern Pacific. The early, Chlamys stage of Hinnites corallinus of the eastern Atlantic off west Africa (see preceding discussion of the tribe Chlamydini) is similar but differs in having more prominent and persistent first-order radial plicae and in having less numerous secondary intercalated radials. Among Indo-Pacific Laevichlamys, the species that is closest in morphology is
L. squamosa (Waller, 1972, pl. 3, figs. 38-41, and Figs. 4j, k, n herein). The latter differs from L. multisquamata in having a narrower umbonal angle (less than 90°) and hence a less flaring aspect, a tendency for scales to be present only on the higher order radial ribs, and in having a less sharply refolded dorsal margin on the right anterior auricle. Living habits.-- Laevichlamys multisquamata lives on tropical or subtropical coral reef fronts, between coral or dead shells or in crevices, at depths generally greater than 30 m to well over 100 m; dead shells have been dredged from depths greater than 200 m (Waller, 1973: 47; Abbott, 1974: 443; Sutty, 1986: 102).
Geographic range.— Throughout the Antilles from Barbados northward to southeastern Florida, the Bahamas, and Bermuda (Waller, 1973: 47) and southward to Brazil. The Brazilian record, not previously reported, is based on a right valve found by me in the Paris Museum Collection, where it had been incorrectly identified as Chlamys ornata. It is from Calypso Station 45, 11° 22.5' S, 37° 10' W, from a depth of 3 1 m. A second specimen from Brazil, but without locality details, is present in the BMNH collection. A label indicates that it had been identified by Bavay as "squamosus var. " In the southern Caribbean, the species extends westward to Panama (based on a living specimen dredged by the RN Pilsbry of the University of Miami at a depth of 51 m at 9° 24.8' N, 78° 12.7' W (R/V John Elliott Pillsbury Sta. P-417). The species is thus far known from the Gulf of Mexico only from the deep Flower Garden Reef off the Texas coast (Boone, 1978).
Stratigraphic range.— Lower Pleistocene to Recent.
Laevichlamys multisquamata has not previously been reported from the fossil record. In the present study, specimens of this species were found in unidentified collections from the Pleistocene reef deposits of Barbados (BMNH), from undated beds in northern Cuba that are probably no older than Pleistocene in age (PRI), and from the Moín Formation of Costa Rica (USNM). Also, D. G. Robinson (pers. comm., August, 1992) reported finding this species in the topmost beds of the Moín Formation of Costa Rica between plates of the coral, Agaricia Lamarck, 1801. The Moín Formation, considered in the past to be early to middle Pleistocene in age (Akers, 1972: 44; Robinson, 1990, 1992), has more recently been considered to include upper Pliocene sediments, although the uppermost part of the formation is still dated as early Pleistocene (Coates et al. 1992). Discussion.— As outlined in the previous discussion of evolution within the tribe Chlamydini, it seems very likely that the ancestor of Laevichlamys multisquamata was a species present in the eastern Atlantic during the Late Miocene and Pliocene. Although L. multisquamata at present has a broad distribution in the Caribbean region and has been collected from the Caribbean coast of Panamá, no geminate or sister species are known from the eastern Pacific. This would suggest that the origin or at least the dispersal of the species to the western Atlantic has occurred since the closure of seaways by the rise of the Isthmus of Panamá, i.e. since the middle Pliocene. This is corroborated by the negative evidence of the fossil record; thus far no fossils of this species or probable ancestors have been found in rocks that are known to be older than Pleistocene.»
WALLER, T. R. 1993. The evolution of Chlamys (Mollusca: Bivalvia: Pectinidae) in the tropical western Atlantic and eastern Pacific. American Malacological Bulletin, 10 (2): 195-249, figs. 1-14. [p. 205, 207]
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Laevichlamys multisquamata (Dunker, 1864); T. R. Waller, 1993, The evolution of Chlamys in the tropical western Atlantic and eastern Pacific, figures 4.a- 4.i, l, m.
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«Chlamys multisquamata (Dunker, 1864) is the rarest of the Western Atlantic Chlamys. Originally described from Havana Bay, Cuba, the species was subsequently redescribed as Pecten effluens by Dall (1886) on the basis of two immature valves dredged from 230 m. off Havana. Since this time, additional specimens have been found at Barbados (USM, 46 to 110 m); Dominica (Nat. Marine Fish. Service, Lab. at Pascagoula, Miss., 62 to 110 m); Puerto Rico (USNM, 73 to 91 m); Cuba (USNM, 550 m); Bahamas (USNM, 90 to 550 m); off Palm Beach, Florida (F. M. Bayer Collection, 24 to 30 m); and Bonaine, Dutch West Indies (S. D. Abbott , 17 m. in crevice, on coral heads). At Bermuda, unmistakable fragments of the species were recovered from sediment samples taken on the deepest dive (Station 29, 51 m). According to data accompanying the Palm Beach specimen, the species was living among rocks and between the shells of Spondylus. Morphologically, Chlamys multisquamata resembles several Indo-Pacific species that live in coral crevices (see Waller, 1972). The Western Atlantic species is illustrated in Figures 9-11.»
WALLER, T. R. 1973. The habits and habitats of some Bermudian marine mollusks. The Nautilus, 87 (2): 31-52, figs. 1-33. [p. 47]
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Chlamys multisquamata (Dunker); T. R. Waller, 1973, The habits and habitats of some Bermudian marine mollusks, figures 9-11.
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