Molluscan Larval Shell Morphology

Jablonski, David; Lutz, Richard A.

doi:10.1007/978-1-4899-4995-0_10

Cited by 116 publications

(26 citation statements)

References 140 publications

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“…Larval development was scored for each species as planktonic, planktotrophic or direct, according to the characters of the larval shell (Jablonski and Lutz 1980). In gastropods, a planktotrophic development is denoted by a multispiral protoconch (usually over two whorls, sometimes up to four) comprising a protoconch I and protoconch II, and a clear protoconch/teleoconch separation; a short planktonic but non-planktotrophic development (mostly the Vetigastropoda) is denoted by a very small paucispiral protoconch clearly distinct from the teleoconch; direct development is denoted by a large paucispiral protoconch, usually with an indistinct protoconch/teleoconch transition.…”

Section: Methodsmentioning

confidence: 99%

Mollusca from a species-rich deep-water <em>Leptometra</em> community in the Alboran Sea

Gofas¹,

Salas²,

Rueda³

et al. 2014

Sci. Mar.

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Summary: An exceptional species richness for Mollusca was found on Avempace bank (349-365 m), Djibouti group, Alboran Sea, where the most abundant species was the crinoid Leptometra phalangium. A sample of sediment sieved on a 0.5-mm mesh yielded 156 species of molluscs (83 live-taken, 1772 specimens) with a high Shannon-Wiener diversity index (H' (log2) =3.60). The dominant mollusc was Limopsis aurita and the six most common species accounted for 77% of the specimens. On the other hand, 42 species were represented by only one or two specimens. Two species are described as new, three more are first findings in the Mediterranean and two are first findings in Iberian waters. One-third of the species have not been reported from the neighbouring, well-explored Alboran Island platform. There is a considerable balance between the trophic groups, denoting a stable and structured community. Most of the species have an extensive Atlantic range, and most have a planktonic larval stage. Therefore, it can be hypothesized that the fauna benefits from a diverse influx of larvae carried in by the more superficial incoming Atlantic current. Because of its exceptional richness, this type of bathyal community with Leptometra and Limopsis should be considered a high priority for habitat conservation in the Mediterranean deep sea.Keywords: species diversity; taxonomy; dominant species; trophic structure; geographical distribution; bathyal zone; Leptometra phalangium; marine molluscs. Moluscos de una comunidad profunda de Leptometra rica en especies en el mar de AlboránResumen: Se encontró una excepcional riqueza específica de moluscos en el banco Avempace (349-365 m), grupo de Djibouti, mar de Alborán, donde la especie más abundante fue el crinoideo Leptometra phalangium. En una muestra de sedimento tamizada sobre una malla de 0.5 mm se hallaron 156 especies de moluscos (83 con ejemplares vivos) y 1772 ejemplares, con un alto valor del índice de diversidad Shannon-Wiener (H' (log2) =3.60). El molusco dominante era Limopsis aurita y las seis especies más comunes eran el 77% de los ejemplares. Por otro lado, 42 especies estuvieron representadas únicamente por uno o dos ejemplares. Dos especies se describen como nuevas; tres más son primera cita para el Mediterráneo y dos son primera cita en aguas ibéricas. Un tercio de las especies no están citadas en la plataforma de la vecina isla de Alborán, por su parte bastante estudiada. La representación de los distintos grupos tróficos es equilibrada, denotando una comunidad estable y estructurada. La mayoría de las especies tienen una amplia distribución en el Atlántico y una fase larvaria planctónica. Por lo tanto se supone que la fauna se beneficia de un aporte diverso de larvas por la corriente superficial que entra desde el Atlántico. Por su excepcional riqueza, este tipo de comunidad batial con Leptometra y Limopsis merece considerarse prioritaria para la conservación de hábitats profundos del mar Mediterráneo.Palabras clave: diversidad especifica; taxonomía; especies dominantes; estruc...

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Section: Methodsmentioning

confidence: 99%

Mollusca from a species-rich deep-water <em>Leptometra</em> community in the Alboran Sea

Gofas¹,

Salas²,

Rueda³

et al. 2014

Sci. Mar.

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“…Egg size may give an indication of larval type, but in bivalves a better sign is provided by the sizes of the early larval shells, prodissoconch I and I1 (Jablonski andLutz, 1980, 1983).…”

Section: Latitude (N)mentioning

confidence: 98%

Reproduction in the cold: Thorson revisited

Clarke

1992

Invertebrate Reproduction & Development

118

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Although a tendency for high latitude marine invertebrates to avoid pelagic larval stages was first described in the 19th century, the most detailed early study was that of Thorson in Greenland. This work also established other features of the reproduction of polar marine invertebrates that have become regarded as almost axiomatic (e.g., the release of larvae to coincide with the summer bloom) or largely ignored (a latitudinal cline in egg size within species). This short and selective review examines Thorson's conclusions in the light of recent work. It is now clear that although polar prosobranch gastropods reproduce almost entirely by direct development, for many taxa the real distinction between polar and non-polar species is in the proportion of feeding to non-feeding larvae. Some species release feeding larvae in winter and the energy source for these larvae is obscure. Growth is slow and there is little or no evidence for temperature compensation. Many crustacean species have larger eggs at higher latitudes. Egg size varies significantly within species, with larger eggs being associated with larger females and often reduced fecundity. The reasons for these within-species patterns are currently unresolved.

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“…There are numerous publications on gastropod larval ecology as inferred from protoconch morphology (e.g. Thorson ; Shuto ; Jablonski and Lutz , ; Lima and Lutz ). For operational reasons, the dichotomy planktotrophy vs nonplanktotrophy is used in the present study (see discussion by Jablonski and Lutz , ).…”

Section: Planktotrophy As Inferred From Protoconch Morphology and Dimmentioning

confidence: 99%

“…Also, the evolutionary implications of the larval biology of living gastropods have been intensively investigated and discussed (e.g. Thorson ; Scheltema , ; Shuto ; Bandel , ; Jablonski and Lutz , ; Lima and Lutz ). In most of these studies, the planktotrophic/nonplanktotrophic dichotomy plays an important role, influencing tempo and mode of evolution as well as dispersal and gene flow.…”

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Larval ecology and morphology in fossil gastropods

Nützel

2014

Palaeontology

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The shell of marine gastropods conserves and reflects early ontogeny, including embryonic and larval stages, to a high degree when compared with other marine invertebrates. Planktotrophic larval development is indicated by a small embryonic shell (size is also related to systematic placement) with little yolk followed by a multiwhorled shell formed by a free‐swimming veliger larva. Basal gastropod clades (e.g. Vetigastropoda) lack planktotrophic larval development. The great majority of Late Palaeozoic and Mesozoic ‘derived’ marine gastropods (Neritimorpha, Caenogastropoda and Heterobranchia) with known protoconch had planktotrophic larval development. Dimensions of internal moulds of protoconchs suggest that planktotrophic larval development was largely absent in the Cambrian and evolved at the Cambrian–Ordovician transition, mainly due to increasing benthic predation. The evolution of planktotrophic larval development offered advantages and opportunities such as more effective dispersal, enhanced gene flow between populations and prevention of inbreeding. Early gastropod larval shells were openly coiled and weakly sculptured. During the Mid‐ and Late Palaeozoic, modern tightly coiled larval shells (commonly with strong sculpture) evolved due to increasing predation pressure in the plankton. The presence of numerous Late Palaeozoic and Triassic gastropod species with planktotrophic larval development suggests sufficient primary production although direct evidence for phytoplankton is scarce in this period. Contrary to previous suggestions, it seems unlikely that the end‐Permian mass extinction selected against species with planktotrophic larval development. The molluscan classes with highest species diversity (Gastropoda and Bivalvia) are those which may have planktotrophic larval development. Extremely high diversity in such groups as Caenogastropoda or eulamellibranch bivalves is the result of high phylogenetic activity and is associated with the presence of planktotrophic veliger larvae in many members of these groups, although causality has not been shown yet. A new gastropod species and genus, Anachronistella peterwagneri, is described from the Late Triassic Cassian Formation; it is the first known Triassic gastropod with an openly coiled larval shell.

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Molluscan Larval Shell Morphology

Cited by 116 publications

References 140 publications

Mollusca from a species-rich deep-water <em>Leptometra</em> community in the Alboran Sea

Mollusca from a species-rich deep-water <em>Leptometra</em> community in the Alboran Sea

Reproduction in the cold: Thorson revisited

Larval ecology and morphology in fossil gastropods

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