Gonads are distinct organs in organisms with complicated reproductive systems, and they have specific locations in the body. The gonads of crinoids, however, are scattered in numerous genital pinnules of their arms. We studied seven species of feather stars, Comatella maculata (Carpenter, 1888), Comatella nigra (Carpenter, 1888), Comaster multifidus (M􀎏ller, 1841), Comaster distinctus (Carpenter, 1881), Comanthus parvicirrus (M􀎏ller, 1841), Colobometra perspinosa (Carpenter,1881) and Himerometra magnipinna Clark, 1908 collected at Kenting, southern Taiwan in 2007. The purpose is to explore if the distribution patterns of gonads are adaptative. With bimonthly samplings in a year, it is discovered that the spawning seasons of the species are not synchronized in a particular season. Three models of relationships between maximum arm lengths and numbers of arms exist in the seven species, i.e., constant arm numbers, linear, and quadratic with an asymptote of arm numbers. Therefore, the maximum arm length is more appropriate than arm number as a size index of feather stars. Evidence of bigger mature than immature individuals is found in Comatella maculata, Comaster distinctus and Comaster multifidus, and there is no size difference between males and females. The gonads of feather stars are distributed in the proximal end of arms. The proportion of arms represented by genital pinnules within individuals were constant except in Comanthus parvicirrus where a negative correlation was found. Except the 2 cave-dwelling species, Comatella maculata and Comanthus parvicirrus, most regenerating arms of 5 other species had breakage points occurred near the proximal ends of the arms. Distal breakage may regenerate too fast to recognize. The arms obviously do not grow so fast as to limit gonad development to the proximal ends of arms. Habitat difference may cause variation in genital pinnule widths, but not in the number of genital pinnules as suggested by comparsions of specimens between 2 sites. The cave-dwelling Comanthus parvicirrus has special congregated long arms, which are extended outside. Moreover, these arms have higher probability of breakage, and smaller ranges of genital pinnules than short arms. This phenomenon supports that the limited gonad distribution is adaptive for reducing loss upon arm breakage.

Superfamily Himerometroidea AH Clark, 1908 (Echinodermata: Crinoidea) (formerly Mariametroidea) is the second most speciose superfamily in order Comatulida. Although it includes some of the most common species on tropical western Pacific reefs, its phylogeny is poorly understood. Genus- to species-level taxa are currently distinguished by plastic morphological characters. We revised the superfamily from species- to family-levels using a combined morphological and molecular approach. A phylogeny using two nuclear and three mitochondrial markers recovered Colobometridae and Himerometridae as paraphyletic and Mariametridae and Zygometridae as polyphyletic. Within genus Himerometra (Himerometridae), sequence data and detailed morphological examinations of multiple specimens of H. magnipinna, H. martensi and H. robustipinna indicated that these three taxa are conspecific. A similar examination of specimens attributed on morphological grounds to the genera Dichrometra, Liparometra and Lamprometra (Mariametridae) revealed a lack of substantial enough sequence and morphological differences to maintain them as distinct genera. We have synonymized all three genera and redescribed four species under the senior name Dichrometra. Additional work is needed to more clearly establish characters that will diagnose clades across the superfamily. This study illustrates the importance of reevaluating classifications that incorporate ecophenotypically and ontogenetically variable characters.

Les crinoïdes sont bien connus pour leurs fossiles, mais la biominéralisation de leurs stades larvaires n’est que peu documentée. La première partie du projet présente le développement des ossicules des trois stades larvaires du comatule Florometra serratissima : doliolaria, cystidienne et pentacrinoïde. Les ossicules du crinoïde démontraient de la plasticité phénotypique et de la désynchronisation dans leur développement. Les crinoïdes étant la classe basale des échinodermes modernes, ceci porte à croire que ces traits étaient aussi caractéristiques des échinodermes ancestraux et auraient joué un rôle dans la radiation hâtive et la grande disparité des échinodermes. Pour notre deuxième étude, comme les patrons de morphologie des crinoïdes et des autres échinodermes sont nombreux et sont régulés par des protéines spécifiques, nous avons vérifié la présence de quatre familles de protéines de la matrice de spicules (SMAP) connues chez les oursins dans les transcriptomes des autres échinodermes et d’autres deutérostomes. La famille des spicules matrix (SM) et l’anhydrase carbonique CARA7LA étaient absentes chez tout autre organisme que les oursins, les protéines spécifiques au mésenchyme (MSP130) étaient présentes en nombres différents chez tous les ambulacraires suggérant de multiples duplications et pertes, et les métalloprotéases étaient nombreuses chez chacun. Le développement des ossicules chez les échinodermes est un sujet qui a gagné en popularité au cours des dernières décennies, spécialement chez les oursins, et inclure les crinoïdes dans ce type d’étude permettra de nous renseigner sur l’origine et l’évolution des échinodermes modernes. / While the fossil record of crinoids is widespread and largely known, biomineralization of their larval stages is poorly documented. The first part of the project focuses on the ossicle development of the three larval stages of the feather star Florometra serratissima: doliolaria, cystidean and pentacrinoid. The ossicles of the crinoid showed phenotypic plasticity and asynchronous development. Crinoids form the basal class of living echinoderms; this prompts one to believe that these traits were also characteristic of the ancestral echinoderms and would have played a role in the early radiation and large disparity of the modern echinoderms. For the second study, as patterns of morphology of crinoids and of other echinoderms are numerous and are regulated by specific proteins, we verified the presence of four families of spicule matrix associated proteins (SMAPs) known among sea urchins in transcriptomes of the other echinoderms and deuterostomes. The family of spicule matrix (SMs) proteins and the carbonic anhydrase CARA7LA were absent in any other organism aside from sea urchins, mesenchyme specific proteins (MSP130s) were present in varying numbers in all ambulacrarians suggesting multiple duplications and losses and matrix metalloproteases were numerous in every organisms. The development of ossicles in echinoderms is a topic that has gained popularity in the last decades, especially in sea urchins, and including crinoids in this type of study will inform us about the origin and evolution of the modern echinoderms.