Epitomaptaaumakua sp. nov., a new species of apodous sea cucumber from Hawai`i (Echinodermata, Holothuroidea, Apodida).

Epitomaptaaumakuasp. nov. occurs at a depth of 2.5 m in Kualoa, O`ahu, Hawai`i, living in coarse sand. It is distinctive in having 12 pinnate tentacles, each tentacle with three pairs of digits and 6-8 sensory cups. The body wall bears papillae or oval bumps, and the length of body reaches a maximum length of 18.4 mm after relaxation.

?Holothuria (Lessonothuria) coronata sp. nov. (Echinodermata, Holothuroidea), a new species of sea cucumber from Socorro Island, México.

Holothuria (Lessonothuria) coronatasp. nov. occurs in depths of 5-10 m off the Mexican Pacific coast at the Revillagigedo Archipelago. It is clearly distinguished from other species of the subgenus by the presence of tables with a circular disc and big peripheral holes, sometimes with a second series of peripheral ones, a disc with a spiny or smooth rim and a spire crossed by a single cross-beam, dorsal papillae, and ventral tube feet with curved supporting rods with a spiny edge.

?ResumenHolothuria (Lessonothuria) coronatasp. nov. habita a profundidades de 5­10 m frente a la costa del Pacífico mexicano en el archipiélago de Revillagigedo. Se distingue claramente de otras especies del subgénero por la presencia de tablas con disco circular y grandes orificios periféricos, a veces con una segunda serie de orificios periféricos, disco con borde espinoso o liso y espira con una sola viga transversal, papilas dorsales y pies ambulacrales ventrales con barrotes de soporte curvados, con borde espinoso.

Pentamera fonsecae n. sp. a new species of sea cucumber from the Pacific coast of Costa Rica (Holothuroidea: Dendrochirotida: Thyonidae).

Pentamera fonsecae n. sp. is described from seven specimens as a new species of Thyonidae from the Pacific coast of Costa Rica. It is distinguished from its congeners by having tables with ladder-shaped spires in the body wall, and tube feet with curved support tables of variable height and tables as those found in the body wall slightly smaller than those from the body wall. This species is distributed in Guanacaste, Costa Rica, from 28.5 to 40 m on muddy bottoms.

Epitomaptasimentalae sp. n., a new species of apodous sea cucumber from the Central Eastern Pacific coast of Mexico (Echinodermata, Holothuroidea, Apodida).

Epitomaptasimentalae sp. n. occurs in depths of 4-10 m off the Mexican Central Pacific coast. It is distinctive in having twelve tentacles, each tentacle with two or three pairs of digits and four to six sensory cups, lacking papillae or oval bumps and in reaching a maximum length of 50 mm in life.

ResumenEpitomaptasimentalae sp. n. fue recolectada a profunidades de entre 4­10 m en el Pacífico Central Tropical. Se distingue de sus congéneres por poseer doce tentáculos, cada tentáculo tiene dos o tres pares de dígitos, los cuales a su vez cuentan con cuatro a seis copas sensoriales, no posee papilas o protuberancias ovaladas sobre la superficie del cuerpo y por tener tallas desde los 4 hasta los 50 mm de largo total en ejemplares vivos.

Discovery of Adults Linked to Cloning Oceanic Starfish Larvae (Oreaster, Asteroidea: Echinodermata).

Two juvenile specimens of a new species of Oreaster were collected at Parque Nacional Arrecife Alacranes and Triángulos Oeste in the southern Gulf of Mexico. DNA of mitochondrial loci identifies them as members of the same clade as cloning larvae of Oreaster found abundantly in waters of the Florida Current-Gulf Stream system, and distinct from Oreaster clavatus and Oreaster reticulatus, the two known Oreasteridae species in the North Atlantic. Larvae from the new species of Oreaster persist as clones but also metamorphose and settle to the benthos with typical asteroid morphology.

Morphological comparison of Astropecten cingulatus and a new species of Astropecten (Paxillosida, Astropectinidae) from the Gulf of Mexico.

Astropecten cingulatus is a conspicuous species, which displays a large superomarginal plate series on the abactinal surface. Herein we describe a new species from off the Texas coast that shows the superficial appearance of A. cingulatus, including these large superomarginal plates, but with armature differing from that of typological A. cingulatus. This species shows the actinal surface of the inferomarginal plates without the squamules present on A. cingulatus. In addition, the adambulacral plates possessed but a single central large spine surrounded by a circle of spines rather than spine rows. The abactinal paxillar region was also very narrow. Statistical analysis of these and other morphological characters showed the specimens differed significantly from those of A. cingulatus. The regression of the slope of R:SM# vs. R was significant but the intercept was not. Therefore the two species are indistinguishable at small sizes based on R:SM. Compared to known Atlantic Astropecten spp. these observed characters warrant the description of a new species, Astropecten karankawai, for the specimens from off the coasts of Texas and Mexico.

Lissothuria imbricata sp. nov., a new species of sea cucumber (Echinodermata: Holothuroidea) from the central-eastern Pacific Ocean.

A new species of sea cucumbers of the genus Lissothuria Verrill, 1867 is described. Lissothuria imbricata sp. nov. was found in the central-eastern Pacific Ocean, at 2-16 m depth living on top of rocky reefs, partially covered by algae and organic material. It is distinguished from other species of the genus by having body wall ossicles in form of short, broad towers with a slightly spiny apex, giving the dorsal area a granular appearance. The shape of the ossicles shows some similarities with L. nutriens (H.L. Clark, 1901).

Population size structure and abnormalities in the number of rays of the Sea Star Pentaceraster cumingi (Valvatida: Oreasteridae) in Bahía Chamela, Mexican Pacific / Estructura de tallas poblacional y anormalidades en el número de radios de la estrella de mar Pentaceraster cumingi (Valvatida: Oreasteridae) en Bahía Chamela, Pacífico mexicano

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 abnormalities 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.

Introducción: La Estrella Cojín Pentaceraster cumingi está ampliamente distribuida a lo largo del Pacífico Oriental Tropical. Esta especie produce estrictamente cinco brazos, pero en algunas ocasiones el número puede ser menor o mayor de cinco, o mostrar otro tipo de anormalidad. Objetivo: Evaluar la estructura de tallas poblacional y la presencia de anormalidades en el patrón radial de P. cumingi en la Bahía Chamela, Jalisco, México. Métodos: La población fue monitoreada a lo largo de cuatro años (2016-2019), durante dos periodos estacionales (cálido y templado). Durante el trabajo de campo se recolectó una muestra aleatoria de individuos. Cada estrella de mar fue medida, pesada y revisada para identificar alguna anormalidad en el patrón radial. Resultados: La mayor densidad de individuos se encontró en octubre de 2019 (2.03 ± 0.05 ind/m-2), la menor en marzo de 2017 (0.66 ± 0.13 ind/m-2). Un total de 849 individuos fueron recolectados. Para las estrellas de mar con 5 brazos, la longitud promedio fue de 123.8 ± 15.2 mm y el peso promedio de 326.0 ± 62.4 g. La clase de talla más frecuente varió entre 110 y 120 mm. Del total de individuos muestreados el 0.82 % tuvieron cuatro brazos, el 1.06 % con seis, y el 1.41 % tuvieron un brazo bifurcado. Conclusiones: Se encontraron diferencias en la densidad poblacional y en la estructura de tallas de P. cumingi entre estaciones. Las principales causas de anormalidades en la estrella de mar pueden ser debidas a los cambios que ocurren durante la metamorfosis de las larvas o por una regeneración anormal de los brazos a causa de la depredación.

Annotated checklist for the Gorgonocephalidae family (Echinodermata: Ophiuroidea) from the National Echinoderm Collection "Dra. Ma. E. Caso M." of the Instituto de Ciencias del Mar y Limnología, UNAM / Lista anotada de la familia Gorgonocephalidae (Echinodermata: Ophiuroidea) de la Colección Nacional de Equinodermos "Dra. Ma. E. Caso M." del Instituto de Ciencias del Mar y Limnología, UNAM

Introduction: The order Euryalida is represented by fragile ophiuroids with long and slender arms that can be ramified. Species within the family Gorgonocephalidae are characterized by the presence of tiny hooklets on the dorsal aspect of their arms. There are very few published studies referring to species of the family Gorgonocephalidae inhabiting Mexican waters. Objective: To review the taxonomic status of the species belonging to this taxonomic family, identifying their diagnostic taxonomic characteristics to create an illustrated guide of species kept at the CNE, UNAM. Methods: Specialized bibliography of the Gorgonocephalidae family was gathered. Subsequently, all the specimens from the CNE were photographed using Scanning Electron and Multifocal Microscopy photography, to show the structures of taxonomic relevance. Results: A total of 193 specimens corresponding to eight genera and nine species were reviewed. The genus Astrocaneum presented the highest species richness. Conclusions: For the species identified in this study and for the sake of accurate identification, morphological characters such as the shape of hooklets and arm plates were highlighted.

Introducción: El orden Euryalida está formado por ofiuros frágiles con brazos delgados, largos y a veces ramificados. Las especies de la familia Gorgonocephalidae se caracterizan por la presencia de diminutos ganchos en el lado dorsal de sus brazos. Los estudios que refieren especies de la familia Gorgonocephalidae que habitan en aguas mexicanas son escasos. Objetivo: Realizar la revisión taxonómica de dicha familia, reconociendo los caracteres taxonómicos diagnósticos para generar una guía ilustrada de cada una de las especies que se encuentran en la CNE del ICML, UNAM. Métodos: Se recopiló toda la bibliografía especializada de la familia, posteriormente con ayuda de fotografías de MEB y multifocal se fotografiaron los especímenes de la CNE para destacar las estructuras de importancia taxonómica. Resultados: se revisaron un total de 193 ejemplares correspondientes a ocho géneros, nueve especies, siendo el género Astrocaneum el de mayor riqueza específica. Conclusiones: Para las especies identificadas en este estudio, para dar una identificación más precisa, se destacaron los caracteres morfológicos forma de los ganchos y forma de las placas de los brazos.

Taxonomy of family Benthopectinidae (Echinodermata: Asteroidea) in the Mexican waters of the Gulf of Mexico

Introduction: The family Benthopectinidae is composed of deep-sea sea stars distributed in eight genera and approximately 70 valid species. So far, only five species of this family have been reported for the Mexican waters of the Gulf of Mexico. Objective: To provide an updated local taxonomy of this family. Methods: A total of 566 specimens deposited in the Echinoderm National Collection, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, and the National Museum of Natural History, Smithsonian Institution, collected from 1952 to 2015, were taxonomically examined. Results: We present descriptions, photographs, and an illustrated dichotomous key for Benthopecten simplex simplex, Cheiraster (Barbadosaster) echinulatus, Cheiraster (Cheiraster) planus, Cheiraster (Christopheraster) blakei, and Cheiraster (Christopheraster) mirabilis in the region. Conclusions: The five studied species represent 6 % of the world biodiversity of the family and can now be identified with the illustrated key.

Introducción: La familia Benthopectinidae está compuesta por estrellas de mar de profundidad distribuidas en ocho géneros y 70 especies válidas aproximadamente. Hasta el momento, se han reportado cinco especies de esta familia para las aguas mexicanas del Golfo de México. Objetivo: Realizar una actualización local de la taxonomía de esta familia. Métodos: Se examinaron un total de 566 especímenes depositados en la Colección Nacional de Equinodermos, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México y el Museo Nacional de Historia Natural, Smithsonian Institution, recolectados de 1952 a 2015. Resultados: Presentamos descripciones, fotografías y una clave dicotómica ilustrada para Benthopecten simplex simplex, Cheiraster (Barbadosaster) echinulatus, Cheiraster (Cheiraster) planus, Cheiraster (Christopheraster) blakei, y Cheiraster (Christopheraster) mirabilis en la región. Conclusiones: Las cinco especies estudiadas representan el 6 % de la diversidad mundial de la familia y ahora pueden ser identificadas con la clave ilustrada proporcionada.

An occurence records database of Irregular Echinoids (Echinodermata: Echinoidea) in Mexico.

BACKGROUND: Research on echinoderms in Mexico began in the late nineteenth century. We present a dataset that includes the taxonomic and geographic information of irregular echinoids from Mexico, housed in four collections: 1) Colección Nacional de Equinodermos "Ma. Elena Caso Muñoz" from the Instituto de Ciencias del Mar y Limnología (ICML), Universidad Nacional Autónoma de México (UNAM); 2) Invertebrate Zoology Collection, Smithsonian Museum of Natural History, Washington, D.C., United States of America (USA); 3) Invertebrate Collection, Museum of Comparative Zoology, University of Harvard, Boston, Massachusetts, USA and 4) Invertebrate Zoology, Peabody Museum, Yale University, New Haven, Connecticut, USA. NEW INFORMATION: A total of six orders, 17 families, 35 genera and 68 species are reported, 37 distributed in the Pacific coast and 31 in the Atlantic coast, none of them was found in both coasts. The most diverse region is the Gulf of California (S=32); the most diverse order is Spatangoida with 31 species reported in mexican waters.

Morphology of endoskeleton and spination in the sea star Midgardia xandaros (Brisingida: Brisingidae) from the Gulf of Mexico / Morfología del endoesqueleto y ornamentación de la estrella de mar Midgardia xandaros (Brisingida: Brisingidae) en el Golfo de México

Introduction: The deep-sea asteroid species of Brisingida have a nearly global distribution but have remained poorly understood due to their deep bathymetric distributions and fragile skeletons. Objective: To describe the external and internal morphology of Midgardia xandaros including the skeletal arrangement, through multifocal and SEM techniques. Methods: We examined a total of 21 specimens, including 27 arm fragments, from the Gulf of Mexico and Honduras. Two specimens were dissected. Results: Detailed descriptions of pedicellariae, abactinal, intercostal, inferomarginal, adambulacral, ambulacral, odontophore, and oral ossicles, and their spines are provided, emphasizing the articulations and muscle attachments. C-shaped valves pedicellariae and small pedicellariae valves with shorter denticulation areas were recognized. Conclusions: The morphological description of M. xandaros is expanded, providing the most extensive description of abactinal, first adambulacral, first and subsequent inferomarginal ossicles, abactinal spines, and C-shaped, crossed pedicellariae, as well as the distal arm plates, for a brisingid species using SEM to date.

Introducción: Las estrellas de mar de profundidad del orden Brisingida tienen una distribución casi global, sin embargo, han sido poco estudiadas debido a su profunda distribución batimétrica y esqueleto frágil. Objetivo: Describir la morfología externa e interna de Midgardia xandaros incluyendo el arreglo de las placas del esqueleto mediante técnicas de microscopía multifocal y electrónica de barrido (MEB). Métodos: Se examinó un total de 21 ejemplares, incluyendo 27 fragmentos de brazos, provenientes del Golfo de México y Honduras. Dos de estos ejemplares fueron disectados. Resultados: Se presenta la descripción de pedicelarios; placas abactinales, intercostales, inferomarginales, adambulacrales, ambulacrales, orales y odontóforo, y sus espinas, enfatizando los sitios de articulaciones e inserción de músculos. Se reconocieron pedicelarios con valvas con forma de C, y pequeños pedicelarios cuyas valvas poseen áreas de denticulación cortas. Conclusiones: La descripción morfológica de M. xandaros es ampliada, presentado por primera vez la morfología de las placas abactinales, primera adambulacrales, primera y subsecuentes inferomarginales, espinas abactinales y pedicelarios con valvas con forma de "C", así como las placas distales de los brazos para una especie del orden Brisingida.

Biodiversidad de ofiuroideos (Echinodermata: Ophiuroidea) del talud de la Península de Yucatán, México / Biodiversity of ophiuroids (Echinodermata: Ophiuroidea) from the slope of the Yucatan Peninsula, Mexico

Introduction: The Ophiuroidea class is the most diverse of the Phylum Echinodermata, with 2 064 described species, which can be found from intertidal zones to abyssal depths, but the fauna of Yucatan peninsula needs more study. Objective: To describe the diversity of ophiuroids in the Yucatan continental slope. Methods: Information was compiled from four oceanographic surveys carried out in August 2005, June 2007 (BIOREPES 1 and 2: BRP1 and BRP2), April 2011 and August 2014 (COBERPES 2 and 6: CBP2 and CBP6). The specimens were obtained by trawling with a shrimp net in soft substrates and with a skimmer-type trawl dredge at a depth range of 200 to 1 071 m off the states of Yucatán and Quintana Roo, Mexico. Results: We found members of two superorders, five orders, six suborders, five superfamilies, 18 families, 28 genera and 43 species. Conclusions: The northeast zone Yucatan Peninsula has at least 43 species, of which 19 are new records for the area.

Introducción: La clase Ophiuroidea es la más diversa del Phylum Echinodermata, con 2 064 especies descritas, que se pueden encontrar desde zonas intermareales hasta profundidades abisales, pero la fauna de la península de Yucatán necesita más estudio. Objetivo: Describir la diversidad de ofiuroideos en el talud continental de Yucatán. Métodos: Se recopiló información de cuatro estudios oceanográficos llevados a cabo en agosto de 2005, junio de 2007 (BIOREPES 1 y 2: BRP1 y BRP2), abril de 2011 y agosto de 2014 (COBERPES 2 y 6: CBP2 y CBP6). Los especímenes se obtuvieron mediante la pesca de arrastre con una red camaronera en sustratos blandos y con una draga de arrastre tipo skimmer en un rango de profundidad de 200 a 1 071 m frente a los estados de Yucatán y Quintana Roo, México. Resultados: Encontramos miembros de dos superórdenes, cinco órdenes, seis subórdenes, cinco superfamilias, 18 familias, 28 géneros y 43 especies. Conclusiones: La zona noreste de la Península de Yucatán tiene al menos 43 especies, de las cuales 19 son nuevos registros para el área.

Primer registro del género Leptopentacta (Cucumariidae: Colochirinae) en el Caribe nicaragüense / First record of the genus Leptopentacta (Cucumariidae: Colochirinae) for the Nicaraguan Caribbean

Introducción: El género Leptopentacta solo ha sido reportado previamente en Florida, Cuba, Colombia, Costa Rica y Surinam. Objetivo: Presentar el primer registro del género para Nicaragua. Métodos: Los caracteres morfológicos del material nicaragüense del Smithsonian Institution (USNM 1014529), fueron corroborados con la descripción original. Resultados: Los cinco especímenes recolectados en el Caribe nicaragüense coinciden con el género. Conclusiones: Leptopentacta se reporta por primera vez en el Mar Caribe de Nicaragua. Esto aumenta el número de equinodermos nicaragüenses a 194 especies.

Introduction: The genus Leptopentacta has only been previously reported from Florida, Cuba, Colombia, Costa Rica, and Suriname. Objective: To present the first record of the genus for Nicaragua. Methods: The morphological characters of Nicaraguan material at the Smithsonian Institution (USNM 1014529), were corroborated with the original description. Results: The five specimens collected in the Nicaraguan Caribbean match the genus. Conclusions: Leptopentacta is reported for the first time from the Nicaraguan Caribbean Sea. This increases the number of Nicaraguan echinoderms to 194 species.

Ontogenetic variation of the odontophore of Luidia superba (Asteroidea: Paxillosida) and its taxonomic implications / Variación ontogenética del odontóforo de Luidia superba (Asteroidea: Paxillosida) y sus implicaciones taxonómicas

Introduction: The sea star odontophore is the structure positioned between the paired oral ossicles, with which they articulate through proximal and distal processes. The internal anatomy structures may be used as taxonomic characters for a precise differentiation between species, so it is necessary to describe the structures variation throughout growth. Objective: To describe the odontophore shape and variation of Luidia superba A. H. Clark, 1917 from specimens of the Gulf of California deposited in the Echinoderm National Collection, ICML UNAM. Methods: A total of 735 specimens were examined to describe the external characters, from which 55 selected specimens, within a range of R = 14 mm and R = 210 mm, were dissected to extract the odontophores and analyzed with geometric morphometrics. Results: Scanning electronic microscopy (SEM) images of the odontophores showing the variations in shape throughout growth are presented. Differences in shape between size groups were confirmed with a Canonical Variables Analysis (P < 0.05). Conclusions: There are three main groups in this size ranges where specialization of the stereom can be observed through the ontogenetic series; the variation in shape of the odontophore shown here is a precedent for the use of internal anatomy as new taxonomic characters of identification.

Introducción: El odontóforo es la estructura posicionada entre las placas orales pareadas con las que se articula a través de procesos proximales y distales. Las estructuras de la anatomía interna se pueden usar como caracteres taxonómicos para la diferenciación más precisa entre especies, por lo que es necesario describir la variación de las estructuras a lo largo del crecimiento. Objetivo: Describir la forma y la variación del odontóforo de Luidia superba A. H. Clark, 1917 de ejemplares del Golfo de California depositados en la Colección Nacional de Equinodermos, ICML UNAM. Métodos: Se revisaron un total de 735 ejemplares para describir los caracteres externos y de las cuales se seleccionaron 55 ejemplares, dentro de un intervalo de R = 14 mm a R = 210 mm, de los cuales se extrajeron los odontóforos y fueron analizados utilizando morfometría geométrica. Resultados: Se presentan imágenes de microscopía electrónica de barrido (MEB) de los odontóforos que muestran las variaciones de la forma durante el crecimiento. Se confirmaron diferencias significativas de la forma entre los grupos de tallas mediante un CVA (p< 0.05). Conclusiones: Se observa especialización del estereoma a lo largo de la serie ontogenética; la variación en la forma del odontóforo aquí mostrada es precedente para el uso de estructuras de la anatomía interna como nuevos caracteres de identificación.

Los ofiuroideos (Echinodermata: Ophiuroidea) de la bahía de Chamela, Jalisco, México / Ophiuroids (Echinodermata: Ophiuroidea) from Chamela bay, Jalisco, Mexico

Introducción: La bahía de Chamela está ubicada en la parte central de la costa del estado de Jalisco, México y es un importante área natural protegida. Pese a ello, el estudio de los equinodermos en la zona es incipiente. Objetivo: Proporcionar una lista de verificación actualizada, descripciones de las especies y una clave taxonómica de los ofiuroideos de la bahía de Chamela. Métodos: Recolectamos en la bahía de 1998 a 2018, y también analizamos información de la literatura y especímenes en colecciones científicas internacionales. Resultados: se reportan 19 especies de ofiuroides para el área de estudio, distribuidas en dos órdenes, siete familias y 11 géneros. Ocho de estos corresponden a nuevos registros para el área y tres posiblemente representan nuevas especies. La biodiversidad de ofiuroideos en la bahía de Chamela representa el 15.2% de las especies de ofiuroides del Pacífico mexicano y el 73% de Jalisco. El número de equinodermos conocidos en la bahía de Chamela aumenta a 48 especies. Conclusiones: Se presenta el listado más completo de la clase Ophiuroidea en la bahía de Chamela, Jalisco. La información proporcionada se puede utilizar para otras áreas del Pacífico oriental. La bahía de Chamela es importante en términos de riqueza de especies debido a su heterogeneidad ambiental y numerosas islas.

Introduction: Chamela bay is located in the central portion of the coast from the Jalisco state, Mexico and is an important protected natural area. Despite this, the study of echinoderms in the area is incipient. Objective: To provide an updated checklist, descriptions of the species and a taxonomic key of the ophiuroids from Chamela bay. Methods: We collected specimens from 1998 to 2018, and also analyzed information from the literature and specimens deposited at international scientific collections from Chamela bay. Results: 19 species of ophiuroids are reported for the study area, distributed in two orders, seven families, and 11 genera. Seven of these correspond to new records for the area, one to a new record for Jalisco state, and two possibly represent new species. The biodiversity of ophiuroids in Chamela bay represents 15.2 % of ophiuroid species from the Mexican Pacific and 73 % from Jalisco. The number of known echinoderms in Chamela bay is increased to 48 species. Conclusions: The most complete checklist of the class Ophiuroidea in Chamela bay, Jalisco, is presented. The information provided can be used for other areas of the eastern Pacific. Chamela bay is important in terms of species richness due to its environmental heterogeneity and numerous islands.

Morfología y crecimiento relativo en Clypeaster europacificus (Clypeasteroida: Clypeasteridae) del Golfo de California / Morphology and relative growth in Clypeaster europacificus (Clypeasteroida: Clypeasteridae) from the Gulf of California

Introducción: Clypeaster europacificus es una especie de galleta de mar que se distribuye de 0 a 200 m en el Golfo de California. Objetivo: Describir la morfología y el crecimiento relativo en la testa de C. europacificus. Métodos: Medimos 1 846 especímenes de museo de C. europacificus (N = 1 846) y analizamos el patrón de crecimiento en 32 especímenes de Baja California Sur, México (64 m de profundidad). Estudiamos cinco variables: radio mayor (R) (variable independiente), radio menor (r), longitud del pétalo anterior (LP), área total de prueba (A) y peso seco (P). Resultados: El área de cobertura del petaloide y el contorno de la testa son los caracteres taxonómicos importantes para C. europacificus: los especímenes van desde casi redondos en especímenes pequeños (≤ 3 cm de radio) a ondulados, enfatizando un contorno pentagonal, en organismos más grandes (≥ 3,1 cm de radio). Conclusiones: Existe un crecimiento alométrico negativo en las relaciones R vs. r, R vs. A y R vs. P; mientras que la relación R vs. LP tiene un crecimiento alométrico positivo.

Introduction: Clypeaster europacificus is a species of sand dollar found from 0 to 200 m in the Gulf of California. Objective: Describe the morphology and relative growth in the test of C. europacificus. Methods: We measured 1 846 museum specimens of C. europacificus (N = 1 846) and analyzed growth pattern in 32 specimens from Baja California Sur, Mexico (64 m depth). We studied five variables: major radius (R) (independent variable), minor radius (r), length of anterior petal (LP), total test area (A) and dry weight (P). Results: The petaloid cover area and the outline of the test are the important taxonomic characters for C. europacificus: they range from almost round in small specimens (≤ 3 cm in radius) to wavy, emphasizing a pentagonal outline, in larger organisms (≥ 3.1 cm in radius). Conclusions: There is negative allometric growth in the relationships R vs. r, R vs. A, and R vs. P; while the relationship R vs. LP has positive allometric growth.

Biological and taxonomic perspective of triterpenoid glycosides of sea cucumbers of the family Holothuriidae (Echinodermata, Holothuroidea).

Since the discovery of saponins in sea cucumbers, more than 150 triterpene glycosides have been described for the class Holothuroidea. The family Holothuriidae has been increasingly studied in search for these compounds. With many species awaiting recognition and formal description this family currently consists of five genera and the systematics at the species-level taxonomy is, however, not yet fully understood. We provide a bibliographic review of the triterpene glycosides that has been reported within the Holothuriidae and analyzed the relationship of certain compounds with the presence of Cuvierian tubules. We found 40 species belonging to four genera and 121 compounds. Holothurin A and B are the most common saponins for Actinopyga, Holothuria, and Pearsonothuria. The genus Bohadschia presents mainly bivittoside C and D. Actinopyga has only sulfated saponins mainly oxidized, Bohadschia non-sulfated ones mainly non-oxidized, Holothuria and Pearsonothuria contain both types of compounds, mainly oxidized. Within the genus Holothuria, the subgenus Panningothuria only has non-sulfated saponins. The presence of sulfated and non-sulfated compounds seemingly relates to the expellability or the absence of Cuvierian tubules and the temporal or permanent concealing habits of the species. Our study concludes that better insights into the systematic distribution of saponins in Holothuriidae will only be possible if the identifications of the investigated species are confirmed by a taxonomist, especially in this group wherein cryptic species and variation between life-history stages are common and yet poorly understood. Understanding of saponin distribution within the Holothuriidae would also benefit from a stabilization of triterpene glycoside nomenclature.

Micro identificación taxonómica y nuevos caracteres diagnósticos del erizo marino Astropyga pulvinata (Diadematoida: Diadematidae) / Taxonomic microidentification and new diagnostic characters of the sea urchin Astropyga pulvinata (Diadematoida: Diadematidae)

Resumen Astropyga pulvinata es un diademátido que posee cinco pares de series de puntos iridiscentes presentes en los interambulacros. A partir de la observación 20 individuos in vivo a través de un estereoscopio y el análisis con un Microscopio Electrónico de Barrido se identificaron los pedicelarios, las espículas y las rosetas calcáreas de los pies ambulacrales. Los pedicelarios presentes en A. pulvinata son trivalvados y de tres tipos: claviformes (oficéfalos) presentes en ambulacro; tridentados distribuidos en el peristoma; y trifoliados presentes en toda la testa excepto en los interambulacros. Los pedicelarios claviformes son los únicos que no están unidos por un pedúnculo calcáreo de tipo diadematoide. Se obtuvieron diez tipos de espículas de diversos tejidos blandos: uno del intestino; tres de la membrana anal y seis del peristoma, dos de las cuales no han sido descritas hasta el momento. Uno de estos nuevos tipos de espículas reportados posee forma de basto y otro de media luna. De las observaciones in vivo se encontraron puntos iridiscentes más pequeños presentes en el ambitus constituidos por aproximadamente ocho células.

Abstract Astropyga pulvinata is a sea urchin of the family Diadematidae that have five pairs of series of blue iridescent spots on interambulacral zones, from in vivo observation of 20 individuals under stereo-microscope and Scanning Electron Microscope analysis identification, the pedicellariae, spicules, and calcareous rosettes. The pedicellariae of A. pulvinata have three valves and are of three types: claviform, present on ambulacres; tridentates present on peristome and triphyllous present all over the test except in interambulacral areas. So ophicephalous pedicellariae are not bounded with a calcareous stalk. Ten types of spicules were observed from different soft tissues: one type from the intestine; three from the anal membrane; and six from the peristome, two of them constitute new diagnostic characters. One of them having a bat-shaped form and the other one with a waning crescent shape. In vivo observations showed that the blue iridescent spots were present on interambulacral areas as group of 35 cells bounded, and that other smaller spots were present on the ambitus, composed by eight cells. Rev. Biol. Trop. 63 (Suppl. 2): 49-58. Epub 2015 June 01.