Reproduction Strategies

Awruch, Cynthia A.

doi:10.1016/b978-0-12-801289-5.00007-9

Cited by 25 publications

(23 citation statements)

References 200 publications

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“…Two modes of oviparity, i.e. single and multiple oviparity, are currently recognized in chondrichthyans [1][2][3][5][6][7][8][9][10][11][12] . Single oviparity (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Single oviparity has at least three alternative names, "extended" oviparity 3,4,6,12,14 , "external" oviparity 5,15 , and "simple" oviparity 5 . Multiple oviparity has been also termed "retained" oviparity [3][4][5][6]12,14,16 . These terms are used for the same reproductive mode, and this could lead to confusion and misunderstanding about the oviparity.…”

Section: Discussionmentioning

confidence: 99%

“…Oviparity has been suggested to be the ancestral mode of reproduction for vertebrates 7,44 , and it has also traditionally been believed as the ancestral mode for chondrichthyan fishes 3,14,45 . However, recent studies 5,6,12,46,47 suggest that viviparity is ancestral for all chondrichthyans, with many reversions to oviparity and secondary reversions to viviparity. Phylogenetic interrelationships for the Galeomorphi (orders Heterodontiformes, Orectolobiformes, Lamniformes and Carcharhiniformes) 4,45,[48][49][50] show that short single oviparity is the ancestral mode for the Galeomorphi, and also for the orders Heterodontiformes, Orectolobiformes and Carcharhiniformes.…”

Section: Paritymentioning

confidence: 99%

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Discovery of a new mode of oviparous reproduction in sharks and its evolutionary implications

Nakaya¹,

White

2020

Sci Rep

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Two modes of oviparity are known in cartilaginous fishes, (1) single oviparity where one egg case is retained in an oviduct for a short period and then deposited, quickly followed by another egg case, and (2) multiple oviparity where multiple egg cases are retained in an oviduct for a substantial period and deposited later when the embryo has developed to a large size in each case. Sarawak swellshark Cephaloscyllium sarawakensis of the family Scyliorhinidae from the South china Sea performs a new mode of oviparity, which is named "sustained single oviparity", characterized by a lengthy retention of a single egg case in an oviduct until the embryo attains a sizable length. the resulting fecundity of the Sarawak swellshark within a season is quite low, but this disadvantage is balanced by smaller body, larger neonates and quicker maturation. the Sarawak swellshark is further uniquely characterized by having glassy transparent egg cases, and this is correlated with a vivid polka-dot pattern of the embryos. Five modes of lecithotrophic (yolk-dependent) reproduction, i.e. short single oviparity, sustained single oviparity, multiple oviparity, yolk-sac viviparity of single pregnancy and yolk-sac viviparity of multiple pregnancy were discussed from an evolutionary point of view. The reproductive strategies of the Chondrichthyes (cartilaginous fishes) are far more diverse than those of the other animal groups. Reproduction in chondrichthyan fishes is divided into two main modes, oviparity (egg laying) and viviparity (live bearing). Oviparity is restricted to the orders Carcharhiniformes (ground sharks), Heterodontiformes (bullhead sharks), Orectolobiformes (carpet sharks), Rajiformes (skates) and Chimaeriformes (chimaeras). Viviparity is prevailing in all chondrichthyan orders except in Heterodontiformes and Chimaeriformes whose members are all oviparous. The morphology of members of the order Carcharhiniformes is less diverse compared to those of orders Lamniformes, Orectolobiformes and Squaliformes 1 , but this order is far more speciose, containing more species than in all the other eight shark orders combined. Moreover, the reproductive strategies of carcharhiniform sharks are more diverse than in any other chondrichthyan orders, having two modes of oviparity 1-7 and three or four modes of viviparity 6,7. The catsharks (families Pentanchidae and Scyliorhinidae) are the largest group within the order Carcharhiniformes with about 150 species. Their reproduction is mostly oviparous, with several yolk-sac viviparous species. Among the oviparous catsharks, most of them perform single oviparity, in which one egg case is kept in each oviduct only for a short time and deposited soon after the egg case is completed. The other mode multiple oviparity is found in some catsharks, where several egg cases are retained in an oviduct for months prior to being deposited with a developing embryo in each egg case. Recently, we found a new mode of oviparity in Sarawak swellshark Cephaloscyllium sarawakensis (family Scyliorhinidae, order...

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“…Two modes of oviparity, i.e. single and multiple oviparity, are currently recognized in chondrichthyans [1][2][3][5][6][7][8][9][10][11][12] . Single oviparity (Fig.…”

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Paritymentioning

confidence: 99%

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Discovery of a new mode of oviparous reproduction in sharks and its evolutionary implications

Nakaya¹,

White

2020

Sci Rep

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“…Sawsharks exhibit aplacental viviparity (ovoviviparity), whereby developing embryos within a litter each derive their nutrients from a yolk sac (Awruch, 2015). Ovulated eggs are initially enclosed with an envelope known as the candle, with one egg contained per candle (Hamlett, Knight, Pereira, Steele, & Sever, 2005).…”

Section: Life Historymentioning

confidence: 99%

The Sawshark Redemption: Current knowledge and future directions for sawsharks (Pristiophoridae)

Nevatte

Williamson

2020

Fish and Fisheries

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Sawsharks (Order: Pristiophoriformes, Family: Pristiophoridae) are a highly distinctive group of sharks, characterized by a tapering saw-like rostrum with a pair of elongate barbels on the ventral surface. Their unusual characteristics should attract attention; however, very few studies have been dedicated to sawsharks. As a result, our understanding of their biology and ecology is limited. However, information on aspects of their biology and ecology can be found in studies not directly focussing on sawsharks. This review provides a synthesis of information pertaining to the 10 recognized sawshark species following a comprehensive search of the scientific literature. We cover their distributions, habitat utilization, life histories, reproduction, trophic dynamics and sensory biology. Current knowledge on their unique rostral structures, the evolutionary history of pristiophorids, taxonomy, behaviour and threats to sawshark populations are also reviewed. This compilation serves as a foundation for sawshark researchers and highlights key knowledge gaps in this unique group of elasmobranchs, thereby beginning the sawshark redemption.

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“…A estratégia reprodutiva é classificada quanto ao desenvolvimento (vivíparo ou ovíparo) e tipo de nutrição do embrião (lecitotrófica ou matrotrófica) (Figura 1). A viviparidade é uma característica plesiomórfica no grupo, sendo as formas mais ancestrais a lecitotrófica saco-vitelino e a oofágica, enquanto as formas mais derivadas são a placentotrófica e a histotrófica, na qual as relações materno-fetais são maiores (Hamlett et al, 2005;Awruch, 2016). Os elasmobrânquios não apresentam cuidado parental após o nascimento como visto em outros vertebrados, contudo, ao nascerem os filhotes contam com reservas energéticas de fontes de investimento materno pré-natal, que são estocadas na forma de saco vitelínico interno ou no fígado (Hussey et al, 2010).…”

Section: Fase Neonatal Em Elasmobrânquiosunclassified

Lipídios e isótopos estáveis como indicadores de investimento materno e estratégias nutricionais neonatais em raias vivíparas histotróficas

Rangel¹

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Reproduction Strategies

Cited by 25 publications

References 200 publications

Discovery of a new mode of oviparous reproduction in sharks and its evolutionary implications

Discovery of a new mode of oviparous reproduction in sharks and its evolutionary implications

The Sawshark Redemption: Current knowledge and future directions for sawsharks (Pristiophoridae)

Lipídios e isótopos estáveis como indicadores de investimento materno e estratégias nutricionais neonatais em raias vivíparas histotróficas

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Reproduction Strategies

Cited by 25 publications

References 200 publications

Discovery of a new mode of oviparous reproduction in sharks and its evolutionary implications

Discovery of a new mode of oviparous reproduction in sharks and its evolutionary implications

The Sawshark Redemption: Current knowledge and future directions for sawsharks (Pristiophoridae)

Lipí­dios e isótopos estáveis como indicadores de investimento materno e estratégias nutricionais neonatais em raias viví­paras histotróficas

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Lipídios e isótopos estáveis como indicadores de investimento materno e estratégias nutricionais neonatais em raias vivíparas histotróficas