Sexual and reproductive traits of the pearl oyster shrimp Pontonia margarita (Decapoda: Palemonidae), symbiotically inhabiting the mantle cavity of the rugose pen shell Pinna rugosa (Bivalvia: Pinnidae)

Diego García Ulloa,Andres Martín Góngora Gómez,Jaun Antonio Hernández Sepúlveda,Victor Landa Jaime,Manuel García Ulloa

doi:10.3897/zoologia.36.e29774

Diego García Ulloa, Andres Martín Góngora Gómez + Show 3 more

Open Access

https://doi.org/10.3897/zoologia.36.e29774

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Abstract

Symbiosis between decapods and mollusks provides a unique opportunity to examine some of the evolutionary strategies employed by marine invertebrates. We describe the sexual and reproductive traits of the pearl oyster shrimp, Pontoniamargarita Verril, 1869, found symbiotically inhabiting the mantle cavity of the rugose pen shell, Pinnarugosa Sowerby, 1835. Solitary males and females (ovigerous and non-ovigerous) and heterosexual pairs (with ovigerous and non-ovigerous females) were found in a total of 47 rugose pen shells collected from a sandy area with seagrass meadows on the southeastern coast of the Gulf of California, Mexico. The body length (BL) of female P.margarita was correlated with the shell volume of their rugose pen shell host. The sex ratio was female-biased (0.85M:1F). Female P.margarita were larger than their male counterparts in terms of BL, cephalothorax length (CL), and the maximum chelae length of the second pereopod (MCL). The CL and MCL were more strongly correlated for males (r = 0.70, p = 0.01). The number and volume of eggs per ovigerous female varied from 95 to 1,571 and from 5.46 ± 0.48 to 8.85 ± 0.97 mm3, respectively. Our results indicate polygamous behavior and social monogamy among P.margarita, and a short-term pairing system for their association with P.rugosa.

Highlights

Examples of biological associations between marine invertebrates as evolutionary strategies include small decapods living in or on other organisms, such as anemones, polychaetes, echinoderms, and bivalves (Nizinski 1989, Itani et al 2002, Baeza et al 2013)
We describe the sexual and reproductive traits of P. margarita found symbiotically inhabiting the mantle cavity of Pinna rugosa Sowerby, 1835, reporting new morphological and reproductive indicators to better explain this example of symbiosis as an evolutionary adaptation in the marine environment
A total of 47 rugose pen shell (P. rugosa) specimens were collected by free-diving during diurnal low tides (< 1 m) in the waters surrounding a fishery in Altata Bay (24°38’00”N; 107°55’00”W), Navolato, Sinaloa, Mexico

Summary

INTRODUCTION

Examples of biological associations between marine invertebrates as evolutionary strategies include small decapods living in or on other organisms, such as anemones, polychaetes, echinoderms, and bivalves (Nizinski 1989, Itani et al 2002, Baeza et al 2013). Pacheco et al (2014) observed Pontonia pinnophylax in the mantle cavity of P. rudis, and Baeza et al (2011) discovered the shrimp P. mexicana GuérinMéneville, 1855 in the amber pen shell Pinna carnea Gmelin, 1797. In these studies, both sexual pairs and solitary individuals were reported. We describe the sexual and reproductive traits of P. margarita found symbiotically inhabiting the mantle cavity of Pinna rugosa Sowerby, 1835, reporting new morphological and reproductive indicators to better explain this example of symbiosis as an evolutionary adaptation in the marine environment

MATERIAL AND METHODS

RESULTS

DISCUSSION