Discovery and anatomy of the arenophilic system of cuspidariid clams (Bivalvia: Anomalodesmata)

Abstract

The arenophilic system of anomalodesmatan clams comprises multicellular glands, muscular papillae, and radial lines of adhesive secretion, which glue sand grains and other extraneous particles to the external surface of the shell. The presence and morphology of these organs have been established in an increasing number of taxa, but arenophilic glands were not previously known to occur in the deep-sea, carnivorous family Cuspidariidae. Dissections, histological sections and ultrastructural examination of members of the cuspidariid genera Cuspidaria and Cardiomya revealed a functional arenophilic system positioned around the siphonal apparatus. Glands are contained in muscular papillae at the posterior tip of the siphonal sheath, from where they deposit their adhesive secretion onto the shell rostrum. Discovery of an arenophilic system in cuspidariid clams adds support to the idea that the glands are a synapomorphy of Anomalodesmata, secondarily absent in only one of the major component branches (the clade joining Thraciidae, Cleidothaeridae, and Myochamidae). Moreover, similarity between the arenophilic papillae we observed on the siphonal sheath of Cuspidaria, Cardiomya, and Myonera, and literature reports on the crown of tentacles of Multitentacula is puzzling and highlights the need for further studies of the latter genus.

Septibranchia (Mollusca: Bivalvia) from the North and Northeast Coasts of Brazil

“…Cardiomya cleryana is distinguished from other Cardiomya species found in this study mainly by radial ribs with equal sizes and shortly rostrate posteriorly. The anatomy of the arenophilic system of Cardiomya cleryana was described by Oliveira and Sartori (2014). This study extends the northern distribution limit of C. cleryana in the South-western Atlantic with new records for off the north-north-east coast of Brazil (Amapá, Pará, and Alagoas) and Itamaracá Island, Pernambuco (northeast Brazil).…”

“…(Oliveira 2012;Oliveira and Absalão 2009, 2010a, 2010bAbsalão and Oliveira 2011;Pimpão et al 2010;Oliveira and Sartori 2014)) the knowledge about these families is still far from complete, as shown by the new records done in this study. The present study shows the possibility of two new species of septibranchs to Brazil.…”

Functional morphology ofCardiomya cleryana(d'Orbigny, 1842) (Bivalvia: Anomalodesmata: Cuspidariidae) from Brazilian waters: new insights into the lifestyle of carnivorous bivalves

“…The arenophilic glands (ag) are characterized by a core (cg) and a duct (gd) that in living individuals extends outwards forming a small U-shaped papilla (Figure 4G, H). In fixed individuals these glandular papillae and their ducts are inverted (Oliveira & Sartori, 2013, figure 3). Using SEM, the glandular papillae can be observed easily on the surface of the siphons and are cylindrical in shape sometimes with a constriction apically (Figure 4E).…”

The organs of prey capture and digestion in the miniature predatory bivalveSpheniopsis brasiliensis(Anomalodesmata: Cuspidarioidea: Spheniopsidae) expose a novel life-history trait

“…In a series of studies, Morton (1981Morton ( , 1982Morton ( , 1984Morton ( , 2003 undertook investigations of the anatomies of Poromya granulata (Nyst and Westendorp, 1839) (Poromyidae), Parilimya fragilis (Grieg, 1920) (Parilimyidae), Lyonsiella formosa (Jeffreys 1881) and Bentholyonsia teramachii (Habe, 1952) (Lyonsiellidae), also reviewing statocyst and siphon structure in representatives of the various families (Morton 1985(Morton , 1987. Nakazima (1967) studied the anatomy of Halicardia nipponensis Okutani, 1957 (Verticordiidae), while Oliveira and Sartori (2013) examined the arenophilic radial glands in the siphons of Cuspidaria obesa and a species of Cardiomya. Reid and Reid (1974) examined aspects of the anatomy and behaviour of Cuspidaria rostrata (Spengler, 1793) and C. obesa (Lovén 1846) and Reid and Crosby (1980) subsequently undertook a study of how Cardiomya planetica (Dall, 1908) captured its prey.…”