First report of an egg-predator nemertean worm\xa0in crabs from the\xa0south-eastern Pacific coast:\xa0Carcinonemertes camanchaco sp. nov

Natalia Verónica Leiva,Juan Antonio Baeza,María Teresa González,Luis Ñacari

doi:10.1038/s41598-021-98650-0

Natalia Verónica Leiva, Juan Antonio Baeza + Show 2 more

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https://doi.org/10.1038/s41598-021-98650-0

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Journal: Scientific Reports	Publication Date: Oct 12, 2021
Citations: 2	License type: open-access

Affiliation: University of Antofagasta

Abstract

Nemertean worms belonging to the genus Carcinonemertes have been tied to the collapse of crab fisheries in the northeastern Pacific Ocean. A new species is described from egg masses of two commercial crabs, Cancer porteri and Romaleon setosum, inhabiting the central-north Chilean coast. This is the first species of Carcinonemertes described from the southeastern Pacific Ocean. Total body length of Carcinonemertes camanchaco sp. nov. ranged from 2.38 to 4.93 and from 4.29 to 8.92 mm, in males and females, respectively. Among others, traits that distinguish this new species from other previously described congeneric species include: presence of two gonad rows on each side of the intestine, a simple (not decorated) mucus sheath, and a relatively wide stylet basis. Maximum likelihood and Bayesian inference phylogenetic analyses distinguished this new species from all other species of Carcinonemertes with available cox1 sequences in GenBank. Prevalence and mean (± SD) intensity of C. camanchaco sp. nov. was 24% and 2.6 (± 2.07) worms per egg mass in C. porteri and 38.1% and 3.8 (± 2.4) worms per egg mass in R. setosum. The formal description of this new species represents the first step towards the understanding of this worm's impact on the health of crab fisheries in the southeastern Pacific Ocean.

Highlights

Nemerteans belonging to the family Carcinonemertidae are voracious egg-predators that infect a variety of decapod crustaceans[1,2]
Range 2.381–4.929 0.143–0.286 0.014–0.030 0.007–0.030 0.070–0.162 0.090–0.133 0.117–0.200 0.026–0.075 0.102–0.222 0.048–0.100 0.045–0.080 0.026–0.075 0.030–0.061 0.100–0.256 0.042–0.052 0.006–0.020 0.005–0.006 0.020–0.037 0.010–0.020 0.167–0.800 0.183–0.305. This is the first study that has tested for the presence/absence of nemertean egg-predators in commercial crabs from the South-eastern Pacific Ocean (SEP) coast
We did find nemertean worms infecting two species of crabs from the SEP and our morphometric and molecular analyses indicated that these nemerteans parasitizing eggs of Romaleon setosum and Cancer porteri belong to the same species of Carcinonemertes, here named C. camanchaco sp. nov

Summary

Introduction

Nemerteans belonging to the family Carcinonemertidae are voracious egg-predators that infect a variety of decapod crustaceans[1,2]. Some nemertean parasites exhibit a rather simple and short life cycle in which the worms feed, mature, and reproduce on a single ovigerous female host. In this case, host autoinfection is common Landings diminished from 548 to 216 tons in the same period for R. setosum[32] This steady temporal decrease in landed biomass has forced the implementation of specific management strategies for the two crab species, including a full fishery ban in the case of C. porteri[28]

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