Experiments in nature and laboratory observations with Nausithoe aurea (Scyphozoa: Coronatae) support the concept of perennation by tissue saving and confirm dormancy

Abstract

Stephanocyphistomae of Nausithoe aurea from São Paulo State, Brazil (in subtropical western South Atlantic waters), were relocated with their substrata in nature to study their survivorship under control and and experimental seriesi.e. the polyps in the original orientation and inverted, and in each series exposed and buried polyps. We found that N. aurea survives over 13 months in nature, between 1/3 -1/4 of 268 stephanoscyphistomae as normal feeding polyps, by segmentation produces planuloids and rejuvenates the polyps -an additional explanation for clustering of the solitary stephanocyphistomae. Dormant living tissues within the periderm of the tube were considered resting stages. The results support the concept that coronates in general have the capacity to save all living tissue and transform it to the energy saving sessile stage -the perennial polyp.Key-words: Cnidaria, Scyphozoa, Nausithoe aurea, perennation, resting stages, Brazil. ResumoEstefanocifístomas de Nausithoe aurea no Estado de São Paulo, Brasil (em águas subtropicais do Atlântico Sul ocidental), foram realocados com os seus substratos na natureza para estudar a sobrevivência em séries controle e experimental -isto é, os pólipos na posição original e invertidos e em cada série pólipos expostos e enterrados. Verificamos que N. aurea sobrevive por 13 meses na natureza, entre 1/3 -1/4 de 268 estefanocifístomas como pólipos normais capazes de alimentação, por segmentação produz planulóides e rejuvenesce o pólipo -uma explicação adicional para a ocorrência agregada dos estefanocifístomas solitários. Tecidos vivos dormentes dentro da periderme do tubo foram considerados como estágios de quietação. Os resultados reforçam a idéia de que os coronados em geral têm a capacidade de conservar todo o tecido vivo e de transformá-lo durante o estágio séssil mais econômico energeticamente -o pólipo perene. Cnidaria, Scyphozoa, Nausithoe aurea, perenização, estágios de quietação, Brasil. Palavras-chave:

Ectodermal origin and tissue dedifferentiation in the podocyst production by the polyps of the Asian moon jelly (Aurelia coerulea)

“…It remains unclear whether the morphological similarities between podocysts and planulocysts are merely convergent for dormancy or genetically related. Another dormant form in Scyphozoa is contracted polyps, which are degenerated polyps retracted into their chitinous peridermal tubes, observed in coronate species such as Nausithoe maculata (formerly named N. aurea ) and Nausithoe racemosa (formerly named Stephanoscyphus racemosus ) (Silveira et al, 2002; Werner, 1970). This dormant form has chitinous peridermal tubes to protect somatic tissues like podocysts, although the tissues have a diploblastic structure as the result of weak degeneration of whole polyps (Silveira et al, 2002).…”

“…This morphological feature distinguishes contracted polyps from podocysts. Furthermore, unlike podocysts, planulocysts and contracted polyps have no role in asexual reproduction (Holst et al, 2024; Silveira et al, 2002). Therefore, podocysts appear to be evolutionarily and developmentally distinct from the other two dormant forms in Scyphozoa.…”

“…This morphological feature distinguishes contracted polyps from podocysts. Furthermore, unlike podocysts, planulocysts and contracted polyps have no role in asexual reproduction (Holst et al, 2024;Silveira et al, 2002).…”

“…Nausithoe racemosa (formerly named Stephanoscyphus racemosus) (Silveira et al, 2002;Werner, 1970). This dormant form has chitinous peridermal tubes to protect somatic tissues like podocysts, although the tissues have a diploblastic structure as the result of weak degeneration of whole polyps (Silveira et al, 2002). This morphological feature distinguishes contracted polyps from podocysts.…”

Coloniality, clonality, and modularity in animals: The elephant in the room

“…It is the case of hydrozoan known as "immortal jellyfish" ( Turritopsis ; Piraino, Boero, Aeschbach, & Schmid, 1996), in which the mature reproducing medusa can degenerate, undergo cellular reorganization, and form a new larval polyp. Some scyphozoans show similar simplification processes (He, Zheng, Zhang, & Lin, 2015), which have been described as “tissue saving” (Silveira, Jarms, & Morandini, 2002) or “reverse development” (Piraino, de Vito, Schmich, Bouillon, & Boero, 2004).…”