taxonID	type	description	language	source
432095476A41FFA3FC79D49BAA84F925.taxon	diagnosis	Diagnosis Test of adults very high, ovoid in aboral view, and compressed laterally with low ambitus; anterior end rounded without frontal groove; posterior end almost vertically truncated. Large spoon-shaped spines present on plastronal area; frills of large paddleshaped spines around periproct and aborally on the posterior end; subanal tuft of large pointed spines. Other significant features are important in identification of the genus but are present in other holasteroids and therefore not diagnostic for Calymne alone. These are as follows. Orthosternous plastron with small labrum in contact with sternal plate; interambulacra 1 and 4 meridoplacous, interambulacra 2 and 3 amphiplacous in adults; anterior and posterior pairs of genital plates separated by pair of ocular plates; two gonopores on genital plates 2 and 3. Uniporous ambulacra. Peristome flush with test; periproct supramarginal, located at top of posterior face. Marginal orthofasciole crossing plates 5. a. 4 and 5. b. 5. Rostrate pedicellariae of three types; ophicephalous pedicellariae umbrella-shaped; triphyllous pedicellariae present; tridentate and globiferous pedicellariae absent. Genotype and only known species: Calymne relicta.	en	Saucede, Thomas, Mironov, Alexander N., Mooi, Rich, David, Bruno (2009): The morphology, ontogeny, and inferred behaviour of the deep-sea echinoid Calymne relicta (Holasteroida). Zoological Journal of the Linnean Society 155 (3): 630-648, DOI: 10.1111/j.1096-3642.2008.00461.x, URL: https://academic.oup.com/zoolinnean/article-lookup/doi/10.1111/j.1096-3642.2008.00461.x
432095476A41FFA2FC72D04CAE7CFE41.taxon	diagnosis	Diagnosis As for the genus.	en	Saucede, Thomas, Mironov, Alexander N., Mooi, Rich, David, Bruno (2009): The morphology, ontogeny, and inferred behaviour of the deep-sea echinoid Calymne relicta (Holasteroida). Zoological Journal of the Linnean Society 155 (3): 630-648, DOI: 10.1111/j.1096-3642.2008.00461.x, URL: https://academic.oup.com/zoolinnean/article-lookup/doi/10.1111/j.1096-3642.2008.00461.x
432095476A4DFFB1FC5DD230AAA0FBCD.taxon	description	Morphology-based interpretations of the mode of life of atypical irregular echinoids such as Calymne are necessarily hypothetical, and require confirmation by vehicle-based direct observation (Southward et al., 1976; David & Sibuet, 1985; Lauermann & Kaufmann, 1998). Fortunately, in irregular sea urchins, many characteristics of the test permit inferences concerning their behaviour and Calymne is no exception. When morphological characters are considered, comparisons with analogous (and sometimes even homologous) structures found in spatangoids – the closest relatives of holasteroids (Mintz, 1968; Smith, 1984) – take functional analysis from the realm of speculation to that of testable hypotheses. Correlations between actual behaviour of spatangoids and their functional morphology have been studied in detail and continue to provide reliable results supported by ecological observations (Nichols, 1959 a; Kier & Grant, 1965; Chesher, 1968; Smith, 1980 a, b; Kanazawa, 1992). We feel that observations such as the ones provided above concerning the test and appendages permit robust, testable hypotheses regarding the mode of life of echinoids, because so many of their vital functions, such as locomotion, burial, respiration, and excretion are directly related to skeletal characteristics (Smith, 1984). The most significant morphological features of Calymne that might inform these hypotheses are: the high arch of the test when viewed in profile, the anterior placement of the mouth, the relatively high placement of the periproct on the posterior face of the test, the occurrence of a marginal fasciole, plastronal spines with an apparent reverse power stroke, a subanal tuft, and posterior spine frills on either side of an aboral, posterior bulge in the test. The first step in interpreting Calymne ’ s behaviour is to determine its living position relative to the sea floor. The only robust data we have concern one young specimen found within the first 5 cm of the upper sediment layer in station 2462, cruise 23 of the R / V ‘ Akademik Mstislav Keldysh’. Unfortunately, this is not sufficient to determine with precision Calymne ’ s living position. The problem is confounded by the fact that juveniles of some echinoids can exploit levels in the sediment different from those of their corresponding adults. In addition, interpretations of the position in life for Calymne in particular are made more difficult because seemingly incompatible characters occur together: specialized spines evocative of burrowing forms co-occur with general features unsuited for a permanent infaunal position. From that, it is necessary to consider several hypotheses regarding Calymne ’ s mode of life and ability to burrow.	en	Saucede, Thomas, Mironov, Alexander N., Mooi, Rich, David, Bruno (2009): The morphology, ontogeny, and inferred behaviour of the deep-sea echinoid Calymne relicta (Holasteroida). Zoological Journal of the Linnean Society 155 (3): 630-648, DOI: 10.1111/j.1096-3642.2008.00461.x, URL: https://academic.oup.com/zoolinnean/article-lookup/doi/10.1111/j.1096-3642.2008.00461.x
432095476A4DFFB1FC5DD230AAA0FBCD.taxon	description	INFERRED BEHAVIOUR Most benthic deep-sea animals cannot, energetically speaking, ‘ afford’ a sessile lifestyle. In fact, most of the adaptations to the abyssal benthic lifestyle seem directed towards enhanced mobility in order to exploit opportunistically the occasional rich marine snowfall or patchy distributions of otherwise sparse nutrients. This principle is manifested in several diverse echinoderms: swimming elasipodid holothuroids ‘ leaping’ from place to place (Ohta, 1985); swimming aspidochirote holothuroids undulating above the bottom (Rice et al., 1979); other holothuroids that can walk on enlarged podia (pers. observ.); crawling crinoids (Fujita, Ohta & Oji, 1987); and fast-moving, lightly constructed echinothurioid sea urchins with hooves on their spines (Emson & Young, 1998). These observations reinforce the likelihood that Calymne is epifaunal. However, any such hypothesis of an epifaunal lifestyle must also accommodate the unorthodox position of the fasciole and two groups of spines. First, the occurrence of a marginal fasciole and of a subanal tuft implies that Calymne might live partly buried, the flat oral surface shallowly ploughing the sea floor, mouth-first. In this interpretation, the subanal tuft may be used to stabilize the test on the unstable deep-sea mud. Second, the function of the upper-posterior frills of large spines is difficult to envisage in the context of well-known echinoid behaviours. A superficial examination might lead to a first hypothesis involving cleaning of the test or a covering reaction, but this would depart significantly from all direct observations made on other deep-sea holasteroids (Rice et al., 1979; David et al., 2003 b). A second hypothesis would suggest that the frills help overturned specimens to right themselves. Although it might seem unusual to evolve a specialized spination for this purpose alone, this hypothesis is supported by the shape of the test. It is very high, and therefore likely to be unstable in nearly any current regime, and lacks robust lateral spines that would otherwise perform this righting function. This hypothesis could also explain the spatulate shape of the spines, which is ideally suited for pushing against sediment. The forward motion of Calymne almost undoubtedly results from the coordinated strokes of L 2 and L 3 spines located on the oral surface. In these spines, curvature is orientated forward, allowing efficient contact and thrust upon the substrate. During locomotion, plastronal S 2 spines can rest perpendicular to the test without producing any forward stroke, but would participate in stabilizing the test. The shallow burial could be accomplished by the combined strokes of plastronal (S 2) spines, frontal spines (S 3), and ventro-lateral L 2 and L 3 spines. In this scenario, while ventro-lateral spines excavate that part of the sediment located beneath the test, their action is assisted by a slight rocking movement of the test. This movement, facilitated by the thixotropy of the substrate, would be achieved by the antagonistic and coordinated actions of plastronal and frontal spines. These spines would tilt the test alternatively frontward through action of the frontward stroke of plastronal spines, and then backward by the downward stroke of frontal spines. Rocking movements have already been observed in Brissopsis lyrifera and wedge-shaped spatangoids that rock while burrowing in muddy substrates (Kanazawa, 1992; Hollertz & Duchêne, 2001). If we accept that Calymne is partially infaunal, we might envisage that it uses the phyllopodia to gather and transfer food from the relatively rich upper marine snow layers to the anteriorly placed mouth. One might even suggest that as Calymne does so, it is tilted upward to bring the mouth closer to the upper layers. This rocking behaviour could in fact help to orientate the animal to initiate this ‘ tilted ploughing’. In Calymne, the combination of atypical morphological characters is a challenge to the functional morphological approach, particularly given the lack of detailed knowledge of deep-sea environments. Nevertheless, such morphological inference for function should not be the domain of palaeontology alone. For extant organisms that inhabit environments that remain relatively unexplored, it is necessary to develop hypotheses and even predictions concerning behaviour in order to develop a context for the unusual morphologies these animals represent. With further data from direct deep-sea observation, the soundness of such analyses can only be improved.	en	Saucede, Thomas, Mironov, Alexander N., Mooi, Rich, David, Bruno (2009): The morphology, ontogeny, and inferred behaviour of the deep-sea echinoid Calymne relicta (Holasteroida). Zoological Journal of the Linnean Society 155 (3): 630-648, DOI: 10.1111/j.1096-3642.2008.00461.x, URL: https://academic.oup.com/zoolinnean/article-lookup/doi/10.1111/j.1096-3642.2008.00461.x
