Estrutura populacional de Hyale media (Dana) (Amphipoda, Gammaridea, Hyalidae), habitante dos fitais de Caiobá, Matinhos, Paraná, Brasil

Abstract

ABSTRACT. POPULATION STRUCTURE OF THE SEAWEED DWELLERHYALE MEDIA (DANA) (AMPII IPODA, GAMMARIDEA , HVALlDA E) FROM CAIOBÁ , MATlNIIOS, PARANÁ, BRAZIL.A study ofcolTelation between the tota l body length and the som ites length was c31Tied out in a population of l-fyale media (Dana, 1857), in order to know whi ch somite or group of som ites has the highest correlation index w ith the total body Iength. As the sum ofthe length ofthe first to fourth pereonites showed th e highest linear correlation index (Y=0.0764+0.2736X; r=0.9723), this meristic parameter was chosen to describe the population structure ofthe spec ies. The following aspects were treated: di stributi on of the body size classes in the various phytals, population compos itioll, seasonal Ouctuatioll of population density, relative freq uency of the ov igerous females and correlation between th e body length alld the number of eggs inside the marsupium 01' the ovigerous females. The amphipods were obtained from the seasona l collections of six phyta ls from a rocky seashore of Caiobá, Paraná State: Plerosiphonia pellnala (Roth) Falkenberg, Gymnogongrus griffithsiae (Turner) Martius, Pteroc/adia capillacea (G melin) Bornet & Thured, SargasslIIlI cymosum Garth, GelidiulJI sp and Uiva fasciata Delile; they did not occurred in Padilla gyll7llo;pora (Kútsing) Vickers and POIphyra alropurpurea (O liv i) De Toni. The ai r temperature osc illated from 16°C (winter and autumn) to 23°C (s ummer), the surtàce water temperature from 17°C (winter) to 25°C (summer) and the sllrlàce water salinity , Ii'om 29.3%. (autumn) to 32.8%. (winter). The density ofl-fyale media varied fro m 0.20 ind.g-I (in Uiva) to 26.37 ind.g-I (in Plerosiphonia) ofalga-substratum weigth, and th e population was distribllted mainly in branched a lgae. Tt was detennined three s ize classes in the population, within a range li'om 0.0 I to 2.99m111 of pereonits 1-4 length. Small amphipods prefer finely branched algae like Gyll1l1ogongrus and Pterosiphollia, whereas broad-thallii or less branched a lgae suc h as SargasslIm , Pleroc!adia, Gelidium and Uiva harbour proporcionally high number of large indi viduais. The life cycle of Hyale media takes place wholly in the phytals and the species reproduces cOlltinually ali year round: males, ovigerous females and juveniles are present every season. The highest female reproductive activity occurs in winter and the juveniles are more numerous in Sllmmer. The number of eggs inside the marsupiul11 and the pereonites 1-4 length has a linear correlation (Y=-9,9682+ 12,0729X; 1 = 0.8024).

Macaronesian islands as promoters of diversification in amphipods: The remarkable case of the family Hyalidae (Crustacea, Amphipoda)

“…In amphipods, lacking a larval phase, dispersal mechanisms are limited to rafting objects, anthropic‐mediated transport (Cabezas, Cabezas et al, ; Cowie & Holland, ; Thiel & Gutow, ; Wildish & Pavesi, ) and the overlooked bird‐mediated dispersion (Reynolds, Cumming, Vilà, & Green, ; Viana, Santamaría, & Figuerola, ). Because hyalids typically inhabit algae with high rafting potential, as for example species of the genus Sargassum (Dubiaski‐Silva & Masunari, ), members of this family are assumed to have a reasonable dispersal ability (Deysher & Norton, ; Poore, ). Serejohyale spinidactylus is one of the most prominent examples in this study of the influence of Macaronesia's geodynamics history in the diversification of NEA hyalids, considering the five well‐supported MOTUs recorded, the fairly high average divergence of 12%, and the AMOVA analysis showing that the highest proportion of the genetic variation was observed among the islands.…”

“…Like other peracarideans, development is direct, lacking a larval phase, which restricts species dispersal ability (Naylor, ). The occurrence and abundance of hyalid species are usually related to the complexity of the algal species, with juveniles preferring filamentous algae (e.g., Pterosiphonia , Gymnogongrus ), while the adults occur in less ramified and foliaceous algae (e.g., Sargassum , Gelidium , Ulva ) (Dubiaski‐Silva & Masunari, ; McBane & Croker, ; Moore, ) but they are also reported to have diet preferences in general (Berthelsen & Taylor, ). The exact number of Hyalidae species in NEA is uncertain, but at least 13 species have been reported in this region (De Broyer, Lowry, Jażdżewski, & Robert, ; Horton et al, ; Ruffo, ).…”

“…The exact number of Hyalidae species in NEA is uncertain, but at least 13 species have been reported in this region (De Broyer, Lowry, Jażdżewski, & Robert, ; Horton et al, ; Ruffo, ). Studies addressing the biology of Hyalidae are scarce (Dubiaski‐Silva & Masunari, ; Hiwatari & Kajihara, ; Tsoi & Chu, ), and in the NEA focused mostly on habitat and food preferences (Guerra‐García, Ros, Izquierdo, & Soler‐Hurtado, ; Torrecilla‐Roca & Guerra‐García, ; Vinagre et al, ). The only Hyalidae species investigated in NEA from the genetic viewpoint was Apohyale prevostii (Lobo et al, ; Raupach et al, ), but no molecular data were previously reported for the Macaronesia region.…”