Identification, characterization, and larval biology of a rhizocephalan barnacle, Sacculina yatsui Boschma, 1936, from northwestern Japan (Cirripedia: Sacculinidae)

Gonadal Degeneration and Hepatopancreas Alteration in Orange Mud Crab Scylla olivacea Infected With Sacculina beauforti (Crustacea; Rhizocephala; Sacculinidae)

“…Understanding it could provide clues on the future development of prevention or treatment methods, especially in such case where the host (S. olivacea) is an economically important and highly valuable aquaculture species. The externa anatomy of S. beauforti conforms with the classical externa description of most sacculinids (Lützen and Takahashi, 1997;Alvarez et al, 2009;Kobayashi et al, 2018). The double-layered mantle near the mantle opening of S. beauforti provides additional muscle tissues to perform strong contractions during oviposition, fertilization and expulsion of nauplii (Høeg and Lützen, 1995;Alvarez et al, 2009).…”

“…Also, as most mud crab aquaculture activities are conducted in large earthen ponds with direct water intake from nearby brackish mangrove estuary ecosystems, and infected hosts might be physically healthy until the emergence of externa [which could take months from infection to externa emergence, i.e., 33 days in crab Rhithropanopeus harrissi infected with Loxothylacus panopaei (Alvarez et al, 1995) and 9 months in littoral crab Carcinus maenas infected with Sacculina carcini (Foxon, 1940)], farmers might not be aware of the presence of infected individuals being co-cultured with healthy individuals. Eventually, this could lead to an outbreak of S. beauforti infestation within the culture ponds if mature externae were fertilized by free-living male cyprids (Glenner et al, 2003;Kobayashi et al, 2018) potentially introduced via the water intake system. Therefore, if infected individuals were detected during culture (i.e., with the presence of externa), especially in facilities where water intake is unfiltered and untreated, it is important to remove and discard (kill) them to prevent unwanted outbreaks (Waiho et al, 2021).…”

“…Data were checked for homogeneity of variance using Levene's test and Welch's correction was applied during one-way analysis of variance (ANOVA) if homogeneity of variance is violated (Welch, 1947). Subsequent differences among treatments were detected using Games Howell posthoc test (Kirk, 1995). Multiple regression was conducted, with infection status as dependent variable and sex, CW, BW, GSI and HSI as independent variables to determine if these variables are significant in predicting infection status in S. olivacea.…”

Towards a barnacle tree of life: integrating diverse phylogenetic efforts into a comprehensive hypothesis of thecostracan evolution

“…Rhizocephala are also relatively well-represented in phylogenetic studies. These specialized parasites of crabs and other economically-important crustaceans provide interesting model systems for development and host manipulation (Kobayashi et al, 2018). Fewer studies have considered the placement of the enigmatic Facetotecta, of which only the larvae are known, the Ascothoracida, ectoparasites of cnidarians and echinoderms (Pérez-Losada, Høeg & Crandall, 2009), and the shell-boring Acrothoracica (Lin, Kobasov & Chan, 2016).…”

Morphological and molecular analyses of parasitic barnacles (Crustacea: Cirripedia: Rhizocephala) in Korea: preliminary data for the taxonomy and host ranges of Korean species

“…In contrast to other crustacean species, they have a very simplified external structure (externa) and lack segmentation and appendages in the parasitic stage ( Høeg & Lützen, 1995 ). Due to the simplified morphology of the externa, previous taxonomic studies of rhizocephalans have been based largely on larval morphology and the fine structure of externa observed from paraffin sectioning ( Yoshida et al, 2011 ; Kobayashi et al, 2018 ), with further validation through DNA barcoding analysis ( Yoshida et al, 2012 ; Yoshida, Hirose & Hirose, 2014 ; Høeg et al, 2019 ; Jung, Yoshida & Kim, 2019 ). Very recently, Høeg et al (2019) modified the taxonomic system of Rhizocephala based on molecular phylogenetic analysis of 18S rDNA sequences, and additional molecular-based taxonomy of rhizocephalan barnacles was updated in Chan et al (2021) .…”