Molecular phylogeny of porcelain crabs (Porcellanidae: Petrolisthes and allies) from the south eastern Pacific: the genera Allopetrolisthes and Liopetrolisthes are not natural entities

Extreme diversity and parasitism of Late Jurassic squat lobsters (Decapoda: Galatheoidea) and the oldest records of porcellanids and galatheids

Galatheoid decapod crustaceans consist of ~1250 species today, but their evolutionary history and origin are poorly known. We studied the largest known fossil galatheoid assemblage, from the Late Jurassic of Ernstbrunn, Austria. This coral-associated assemblage yielded 2348 specimens, arranged in 53 species, 22 genera and six families. Rarefaction analyses show that nearly all taxa have been collected. In addition to abundant Munidopsidae, this assemblage also contains the oldest members of four of the six galatheoid families, including Galatheidae, Munididae, Paragalatheidae and Porcellanidae. We describe the oldest Porcellanidae and Galatheidae to date, and a catillogalatheid: Vibrissalana jurassica gen. et sp. nov., ?Galathea genesis sp. nov. and Galatheites britmelanarum sp. nov. Our re-examination of the oldest claimed porcellanid, Jurellana tithonia, from Ernstbrunn, indicates that it represents a homolodromioid brachyuran, ascribed to Jurellanidae fam. nov. along with Ovalopus gen. nov. The second-oldest claimed porcellanid, Early Cretaceous Petrolisthes albianicus, is transferred to the catillogalatheid Hispanigalathea. We further document that 10.4% of Ernstbrunn galatheoid specimens were parasitized by epicaridean isopods, as shown by swellings in the gill region. Statistical analyses indicate that infestation is near non-random, varying from 0 to 33% for common species. Thus, Late Jurassic coral-associated habitats were key ecosystems in the evolution of galatheoids and their parasites.

A new species of Carcinonemertes, Carcinonemertes conanobrieni sp. nov. (Nemertea: Carcinonemertidae), an egg predator of the Caribbean spiny lobster, Panulirus argus

A new species of nemertean worm belonging to the genus Carcinonemertes is described from egg masses of the Caribbean spiny lobster Panulirus argus from the Florida Keys, Florida, USA. This is the first species of Carcinonemertes reported to infect P. argus or any other lobster species in the greater Caribbean and western Atlantic Ocean. Carcinonemertes conanobrieni sp. nov. varies in body color from a translucent white to a pale orange, with males ranging in total body length from 2.35 to 12.71 mm and females ranging from 0.292 to 16.73 mm. Among the traits that separate this new species from previously described species in the genus Carcinonemertes are a relatively wide stylet basis, minimal sexual size dimorphism, and a unique mucus sheath decorated with external hooks. Also, juvenile worms were found to encyst themselves next to lobster embryos and female worms lay both long strings of eggs wound throughout the lobster's setae as well as spherical cases that are attached to lobster embryos. The stylet length and stylet basis remain unchanged throughout ontogeny for both male and female worms. Maximum likelihood and Bayesian inference phylogenetic analyses separated this newly described species from all other species of Carcinonemertes with available COI sequences. Carcinonemertes spp. are voracious egg predators and have been tied to the collapse of various crustacean fisheries. The formal description of this new species represents the first step to understand putative impacts of this worm on the population health of one of the most lucrative yet already depressed crustacean fisheries.