Benthic ctenophore (Order Platyctenida) reproduction, recruitment, and seasonality in south Florida

Abstract

Reproductive structures, modes, and seasonal patterns of size-class abundances are examined in two benthic platyctene (Family Coeloplanidae) ctenophore species present in dissimilar shallow marine environments in subtropical southeast Florida.Coeloplana waltoni, a minute (1-3 mm body length) epizoic associate of octocorals, occurs in exposed environments often under turbulent conditions, and Vallicula multiformis (2-10 mm) commonly occurs epiphytically on macroalgae in protected, calmwater environments. Reproductive activity in C. waltoni is most active during the warm-water summer season (June-October); gonadal development in V. multiformis occurs year-round, and is most pronounced during sea-warming periods in late spring (May) and late summer to early autumn (August-October), with release of cydippid larvae. Both species are hermaphroditic brooders, exhibiting paedogenesis (early gonadal development) at body lengths approximately one-third (Coeloplana) to one-sixth (Vallicula) of maximum adult size. Juvenile individuals (<0.6 mm) increased in abundance in C. waltoni during the summer reproductive period, and large (≥1 mm) pinkcolored individuals comprised 50% or more of samples from July through September.Seasonal abundance of gravid individuals and the timing of cydippid larval release in V. multiformis did not correspond closely with juvenile or adult population densities. Asexual fragmentation occurred in both ctenophore species, but was observed more frequently in individuals of V. multiformis. This asexual mode of reproduction probably accounted in part for the discordance between ctenophore abundances and larval recruitment events by sexual means. Morphological structures and behaviors associated with reproduction are described in this study. Uncommon images of reproductive products (gametes, embryos, larvae), spawning events, brooding, and asexual fragmentation are included, some for the first time in the published literature. K E Y W O R D Sasexual fragmentation, Coeloplana, cydippid spawning, ovoviviparity, Vallicula

First record of a benthic ctenophore in the Mexican Atlantic:Vallicula multiformis(Platyctenida, Coeloplanidae)

“…Despite the different and continuous faunal monitoring (mainly benthic studies) performed by the project BDMY-UNAM in the Mexican Caribbean and the southern Gulf of Mexico, only two individuals of V. multiformis have been observed. The reproductive strategy of this species (Rankin, 1956; Glynn et al ., 2019) allows it to have high abundances during different seasons in some regions of its spatial distribution (e.g. Rankin, 1956; Eldredge and Miller, 1995; Glynn et al ., 2017).…”

Non-native brittle star interactions with native octocoral epizoites: an endemic benthic ctenophore in peril?

“…In just 20 years, individuals of O. mirabilis have colonized coastlines spanning more than 6000 km of latitude (Tavares et al 2021), from their first reported presence in southern Brazil (Hendler et al 2012) northward along the South American coast to the Caribbean Sea (Hendler and Brugneaux 2013;Ferry et al 2020) and southeastern Florida (Glynn et al 2019). Their northern-most occurrence on the Florida east coast, observed on 28 September 2019, was at Deerfield Beach, 26.3184°N, 80.0998°W (Glynn et al 2020).…”

Unravelling the taxonomic identity ofOphiothelaVerrill, 1867 (Ophiuroidea) along the Brazilian coast

“…Ophiothela has a widespread distribution that is continuing to expand. Recently, Ophiothela mirabilis was observed associated with octocorals at Dania Beach, Florida, USA (Glynn et al ., 2019). To date, Ophiothela has not been reported from the northern- and southern-most regions of the Pacific coast of the Americas.…”