94 



J.D. TAYLOR AND E.A. GLOVER 



ABBREVIATIONS 



Institutions: AM - The Australian Museum, Sydney; ANSP - 

 Academy of Natural Sciences, Philadelphia; BMNH - The Natural 

 History Museum, London; MNHN - Museum National d'Histoire 

 Naturelle, Paris; IRSNB - Royal Belgian Institute of Natural Sci- 

 ences; NM - Natal Museum; NMW - National Museum of Wales, 

 Cardiff; NSMT - National Science Museum, Tokyo; SAM - South 

 Australian Museum, Adelaide; USNM - National Museum of Natu- 

 ral History, Washington; UMT - University Museum, Tokyo; WAM 

 - Western Australian Museum, Perth; ZMA - Zoological Museum, 

 Amsterdam; ZMC - Zoological Museum, Copenhagen. 



Shell measurements: H= height of shell from umbone to ventral 

 margin, L = length of shell from anterior to posterior, T= tumidity of 

 shell i.e. maximum convexity measured on a single valve. 



SYSTEMATIC DESCRIPTIONS 



Family LUCINIDAE Fleming, 1828 

 Genus CARDIOLUCINA Sacco, 1901 



Cardiolucina Sacco, 1901: 89. Published June 30 (see Sacco, 1904; 



Marshall, 1991). 

 Bellucina Dall, 1901: 806. Published August 22nd (see Keen, 1971: 



983). Lucina eucosmia Dall, 1901: 806, original designation. 



TYPE SPECIES. Cardium agassizi Michelotti, 1 839 (original desig- 

 nation). 



NOMENCLATURE. The species considered in this paper have usu- 

 ally been assigned to the genus Bellucina Dall, 1901. However, the 

 Miocene C. agassizi Michelotti, the type species of the genus 

 Cardiolucina Sacco 1901, has all the characters of Recent Bellu- 

 cina species (see description and figures of C. agassizi below). 

 Chavan (1937) recognised this and synonymized the two genera 

 giving Bellucina priority. Although published in the same year, 

 Sacco's work appeared in June 1901 (Sacco, 1904, Marshall, 1991) 

 and Dall's in August (see Keen, 1971). Cardiolucina therefore has 

 priority over Bellucina. 



Because the name Bellucina has been commonly used, the con- 

 cept of this genus has to be considered in some detail. Dall (1901, p. 

 806) erected Bellucina as a section of the subgenus Parvilucina 

 within the genus Phacoides. The genus Parvilucina was originally 

 diagnosed as 'Shell small, plump, often inequilateral; sculpture 

 more or less reticulate but not muricate, teeth small, common but all 

 usually present' and the Section Bellucina was rather skimpily 

 distinguished as 'Dorsal areas and sculpture strong.' However, Dall 

 (1901) clearly designated Lucina eucosmia (= L. pisum Reeve) as 

 the type species and the concept of Bellucina must be based upon 

 this species. Many authors (e.g. Fischer, 1871, Lamy, 1920; Chavan, 

 1969;Britton 1972; Bretsky, 1976; Oliver, 1992) have considered B. 

 eucosmia to be synonymous with Bellucina semperiana (Issel, 

 1869). Consequently, the characters of the latter species have been 

 taken to represent Bellucina. Unfortunately, Reeve (1850) mixed 

 two distinct species in the original description and illustrations of 

 Lucina pisum which is clear from the syntype material. Reeve's 

 figure 66a illustrates a specimen from Port Essington, Northern 

 Territory, Australia, and figure 66b shows a shell of another species 

 from Singapore. In the original description of Lucina pisum Reeve 

 clearly referred to the deeply incised lunule and fenestrate ornament 



which are features of the Port Essington specimens. 'Shell globosely 

 cordate, solid, thickly latticed with concentric and radiating ribs, of 

 which the interstices are pitted, posterior side grooved, anterior 

 short, lunule small, deeply excavated; whitish.' For this reason one of 

 the syntypes from Port Essington has been selected as the lectotype 

 of Lucina pisum Reeve (see below under description of Cardiolucina 

 eucosmia). Because the name L. pisum is preoccupied (L. pisum 

 Sowerby, 1836) then C. eucosmia (Dall, 1901) becomes the valid 

 replacement name. The other Reeve syntypes from Singapore we 

 consider to be Cardiolucina semperiana (see below). 



Diagnosis. Shells small but solid, usually less than 14mm in 

 height, subcircular (Height/Length ratio around 1.0), moderately 

 inflated to subspheroidal (Tumidity/Length ratio between 0.38 and 

 0.48). Umbones prosogyrate, more or less central. Anterior sulcus 

 either absent or shallow and narrow. Posterior sulcus always 

 present and either deeply-indented or shallow. Lunule varies in 

 size and depth between species, but where visible it is generally 

 heart shaped. It can be deeply incised and large as in C. eucosmia, 

 or very small and hidden under the beaks as in C. australopilula. 

 Posterior dorsal area distinct, either concave or convex, usually 

 with concentric ribbing. Ornament of radial ribs and concentric 

 lamellae, relative strength of either varies between species. Con- 

 centric lamellae often raised and fluted. Intersection with radial 

 ribs produces a variety of ornament from fenestrate to beaded. 

 Hinge plate thick, dentition of single anterior and posterior lateral 

 and two cardinal teethin each valve. In the right valve of some 

 species one of the cardinal teeth can be either reduced or absent. 

 Ligament external and varying in length; can extend from beaks to 

 position of posterior lateral tooth, or may be two thirds of this 

 distance. Internal ventral margin finely to coarsely crenulate, cor- 

 responding to position of radial ribs. Often small denticles around 

 antero- and postero-dorsal margins. Anterior adductor muscle scar 

 quadrate to elongate, ventral tip only slightly detached from pallial 

 line. Mature individuals of spheroidal species often have the ad- 

 ductor muscle scars located on an internal buttress. Posterior 

 adductor scar short and rounded. 



Juvenile shells are thinner, less inflated, more anteriorly extended 

 with radial ribs often visible from interior of shell. Interior ventral 

 margin not thickened. 



ANATOMY. Based on observations of C. australopilula and C. 

 semperiana. 



Mantle largely unfused except at posterior exhalant aperture. 

 Mantle margin thick and muscular. Mantle 'gills' absent. No fused 

 inhalant aperture. Exhalant aperture a muscular tube with flared 

 distal end, which can presumably be protracted. Ctenidia consist of 

 inner demibranchs only, filaments elongate and thick. Outer lamella 

 of demibranchs attached to posterior mantle just ventral to the 

 exhalent aperture. Labial palps are small ridges at edge of lips. Foot 

 cylindrical and vermiform with a posterior heel. Body wall muscu- 

 lar, with large hemispherical visceral pouch containing oocytes. 

 Rectum curves around dorsal side of the posterior adductor muscle 

 and opens near the posterior aperture. 



Many of the anatomical features, such as the thickened inner 

 demibranchs, reduced labial palps and vermiform foot are similar to 

 those of other lucinids, although some characters may be less widely 

 distributed. A distinctive and possibly functionally important feature 

 is the attachment of the ctenidia to the posterior mantle. It is 

 uncertain how widely this character is distributed amongst the 

 Lucinidae. It was first illustrated by Reid & Brand (1986) for 

 Parvilucina tenuisculpta, but not mentioned by Allen (1958) in his 

 general survey of lucinoids, or by Morton (1979) for Fimbria and not 

 present in Rastafaria (Taylor & Glover, 1997). Large hemispherical 



