Revista de Biología Tropical ISSN: 0034-7744 ISSN: 2215-2075 Universidad de Costa Rica Galván-Villa, Cristian-Moisés; Solís-Marín, Francisco-Alonso Population size structure and abnormalities in the number of rays of the Sea Star Pentaceraster cumingi (Valvatida: Oreasteridae) in Bahía Chamela, Mexican Pacific Revista de Biología Tropical, vol. 69, no. 1, 2021, January-March, pp. 262-273 Universidad de Costa Rica DOI: https://doi.org/10.15517/rbt.v69i1.43239 Available in: https://www.redalyc.org/articulo.oa?id=44967852021 How to cite Complete issue Scientific Information System Redalyc More information about this article Network of Scientific Journals from Latin America and the Caribbean, Spain and Journal's webpage in redalyc.org Portugal Project academic non-profit, developed under the open access initiative ISSN Printed: 0034-7744 ISSN digital: 2215-2075 DOI 10.15517/rbt.v69i1.43239 Population size structure and abnormalities in the number of rays of the Sea Star Pentaceraster cumingi (Valvatida: Oreasteridae) in Bahía Chamela, Mexican Pacific Cristian Moisés Galván-Villa1* & Francisco Alonso Solís-Marín2 1. Laboratorio de Ecosistemas Marinos y Acuicultura, Departamento de Ecología Aplicada, Centro Universitario de Ciencias Biológicas y Agropecuarias, Universidad de Guadalajara, Camino Ramón Padilla Sánchez No. 2100, Nextipac, Zapopan, Jalisco, México. C.P. 45200; [email protected] 2. Colección Nacional de Equinodermos “Dra Ma. Elena Caso Muñoz”, Laboratorio de Sistemática y Ecología de Equinodermos, Instituto de Ciencias del Mar y Limnología (ICML), Universidad Nacional Autónoma de México, Av. Ciudad Universitaria 3000, Coyoacán, Ciudad de México, México. C.P. 04510; [email protected] * Correspondence Received 28-VII-2020. Corrected 20-XI-2020. Accepted 27-XI-2020. ABSTRACT. Introduction: The Panamic Cushion Star Pentaceraster cumingi is widely distributed along the Tropical Eastern Pacific. This species strictly produces only five arms, but sometimes, this number varies or show another kind of abnormality. Objective: We aimed to evaluate the population size structure and abnormali- ties occurrence in the radial pattern of P. cumingi in Bahía Chamela, Jalisco, Mexico. Methods: The population was monitored along four years (2016-2019), in two seasonal periods (warm and cold). During fieldwork, a random sample of individuals was collected. Every starfish was measured, weighted, and evaluated to identify any abnormality on its radial pattern. Results: The highest density of P. cumingi was found in October 2019 (2.03 ± 0.05 ind/m-2), the lower in March 2017 (0.66 ± 0.13 ind/m-2). A total of 849 individuals were collected. For 5-armed starfishes, the average length was 123.8 ± 15.2 mm and the average weight of 326.0 ± 62.4 g. The most frequent length classes ranged from 110 to 120 mm. Of the total of individuals sampled 0.82 % had four arms, 1.06 % six, and 1.41 % had one bifurcated arm. Conclusions: There were differences in the population density and size structure of P. cumingi between seasons. The main causes of abnormalities in the starfish could be due to the changes that occur during larval metamorphosis or by an abnormal regeneration of the arms after a predation attempt. Key words: Sea star; abnormality; density; echinoderm; structure size; Tropical Eastern Pacific. Galván-Villa, C.M., & Solís-Marín, F.A. (2021). Population size structure and abnormalities in the number of rays of the Sea Star Pentaceraster cumingi (Valvatida: Oreasteridae) in Bahía Chamela, Mexican Pacific. Revista de Biología Tropical, 69(1), 262-273. DOI 10.15517/rbt.v69i1.43239 Echinoderms are an ancient lineage of Solís-Marín, & Laguarda-Figueras, 2017). invertebrates that exhibit primitive characters Although asteroids are not typically abundant like autotomy, regeneration, radial symmetry, in marine ecosystems, they influence biodi- and asexual reproduction (James, 1999). The versity, population dynamics, and can exert asteroids (sea stars or starfishes) are present control on community structure as predators in in many different marine environments, from intertidal and subtidal ecosystems (Lawrence, deep abyssal depths to the intertidal zone, from 2013; Menge & Sanford, 2013). the tropics to the poles (Mah & Blake, 2012; Starfish exhibit usually a pentameral sym- O’Hara & Byrne, 2017; Diupotex-Chong, metry, although numerous-armed starfish have 262 Rev. Biol. Trop. (Int. J. Trop. Biol.) • Vol. 69(1): 262-273, March 2021 between six to 40 rays (Hotchkiss, 2000a), e.g., columbiae Gray, 1840 (Fisher, 1945), Nardoa Heliaster helianthus (Lamarck, 1816), Pyc- galatheae (Lütken, 1864) (James, 1999), Pen- nopodia helianthoides (Brandt, 1835), Acan- taceraster regulus (Müller & Troschel, 1842) thaster planci (Linnaeus, 1758). Starfish rays (James, 1999; Shanker & Vijayanand, 2014), exhibit a great variety of functions like loco- Pisaster ochraceus (Brandt, 1835) (Fisher, motion (Migita, Mizukamib, & Gunji, 2005; 1945), and Protoreaster linckii (Blainville, Lawrence, 2013), to force open the shells of 1830) (James, 1999; Chelladurai, Balakrish- mollusks (Lavoie, 1956), parental care (Chia, nan, Jayanthi, Ajeesh-Kumar, & Mohanraj, 1966; Hamel & Mercier, 1995), food detec- 2015; Chelladurai & Doss, 2016). Other spe- tion (Lawrence, 1987; Moore & Lepper, 1997; cies where abnormal ray numbers have been Dale, 1999), to right themselves (Migita et al., recorded include Protoreaster nodosus (Lin- 2005), respiration (Lawrence, 2013), to adhere naeus, 1758), a starfish widely distributed in to the seabed when buffeted by waves (Thomas the Indo-Pacific region (Chim & Tan, 2012) & Hermans, 1985; Santos, Gorb, Jamar, & and Archaster angulatus Müller & Troschel, Flammang, 2005), and to flee under emergency 1842 from the Indian Ocean and western conditions (Emson & Wilkie, 1980). Pacific (Keesing, 2017). Regeneration is a common phenomenon The Panamic Cushion Star Pentaceraster in all actual echinoderm classes (Yousra et al., cumingi (Gray, 1840) (Asteroidea: Oreasteri- 2018; Byrne, 2020). It has been particularly dae) is one of the most common starfish in well-studied in asteroids, where three main the Tropical Eastern Pacific (TEP) (Solís- aspects have been identified: 1) regeneration Marín et al., 2014; Reyes-Bonilla, Vázquez- of body parts (arms) following self-induced or Arce, González-Cuéllar, Herrero-Pérezrul, & traumatic amputation; 2) regeneration of inter- Weaver, 2016). It has a highly variable color- nal organs (pyloric caeca and cardiac stomach) ation, from red-orange or red-green to a gray following self-induced or traumatic mutilation, background color with an overlying bright and 3) fission processes (Candia-Carnevali, red network (Kerstitch & Bertsch, 2007). P. 2006). Regeneration of body parts and envi- cumingi, like most starfish, has pentameric ronmental perturbations on the metamorphosis of larvae can result in an abnormality in the symmetry, is relatively large (up to 17.4 cm number of starfish arms (Hotchkiss, 1979). of diameter), with an inflated body wall, and Worldwide the largest record of occur- immobile spines stud in the upper surface. It is rences of abnormal starfishes have been distributed from the Gulf of California, Mexico reported in India, where at least 13 species to Northern Perú, inhabits rocky reefs, patch have been listed: Anthenea pentagonula reefs, and sandy areas, from low intertidal zone (Lamarck, 1816) (Maheswaran, Narendran, up to 183 m deep (Hickman, 1998; Solís-Marín Yosuva & Gunalan, 2015), Asterina lorioli et al., 2014). Koehler, 1910 (James, 1999), Astropecten indi- The Mexica buried echinoderms in their cus Döderlein, 1888 (James, 1999; Prabhu ritual deposits for at least a half-century. Six & Bragadeeswaran, 2012; Chamundeeswari, species of starfish have been found so far in the Saranya, Shanker, Varadharajan, & Rajagopal, offerings, and the presence of P. cumingi was 2013), A. karankawai Lawrence, Cobb, Her- common (10 000 elements have been found rera, Durán-González & Solís-Marín, 2018 in 13 offerings) (Martín-Cao-Romero et al., (ICMYL Unpublished data), Echinaster pur- 2017). While it is true that many animals (or pureus (Gray, 1840) (James, 1999), Goniodis- artifacts made from them) were buried as gifts caster vallei (Koehler, 1910) (Maheswaran et to the supernatural, in most cases they were al., 2015), Linckia laevigata (Linnaeus, 1758) manipulated as symbols of specific divini- (James, 1999), L. multifora (Lamarck, 1816) ties, of particular regions of the universe, or (James, 1999; Maheswaran et al., 2015), L. of important cosmic processes (López-Luján, Rev. Biol. Trop. (Int. J. Trop. Biol.) • Vol. 69(1): 262-273, March 2021 263 Chávez-Valderas, Zúñiga-Arellano, Aguirre- mouth center to the end of interradius (C-D), Molina, & Valentín-Maldonado, 2012). arm breadth (br) at the base of the A-arm (in It is well known that this starfish forms the case no A-arm, it was replaced with the large aggregations, which may correspond to B-arm), the number of arms, and weight (using feeding (Reyes-Bonilla, González-Azcárraga, a portable electronic balance, 1 g accuracy). All & Rojas-Sierra, 2005) or a reproductive strat- specimens were drained on a plastic tray before egy (Reyes-Bonilla et al., 2016). The Panamic recording the weight, to eliminated variability Cushion Starfish plays an important ecologi- on weighing. Arms position was determined cal role, maintaining the benthic communities following the Carpenter system, which rec- in the TEP by feeding on microorganisms ognized the C- and