A new species and host range of Therodamas (Copepoda, Ergasilidae) from the Eastern Tropical Pacific

Abstract

A new species of the genus Therodamas Krøyer, 1863, one of the three mesoparasitic genera of the copepod family Ergasilidae, is described in detail. The description is based on material collected from the yellowfin snooker (Centropomus robalito Jordan & Gilbert, 1882) from a lagoonal system on the Mexican coast of the Eastern Tropical Pacific. The new species differs from its known congeners in the general structure and proportions of the body and details of the armature of legs 1 and 4. It is most closely similar to T. dawsoni Cressey, 1972 from Panama but differs from this species in several characters including the presence of rounded processes on the antennae, the lack of a spine on the first exopodal segment of leg 4, the presence of four setae on the second exopodal segment of the same leg, and short, spiniform setae on the terminal segments of legs 2 and 3. Species of Therodamas have been hitherto recorded from six teleost families; the finding of the new species from a member of the Centropomidae expands the known host range of this group of ergasilid copepods and confirms the low host specificity of the genus Therodamas, but data suggest that specificity is high at the species level. The genus is restricted to the Neotropical region, but it has not been previously reported from north of Central America; its finding in the tropical Pacific waters of Mexico marks a new latitudinal range for the genus in the Neotropics. It also represents the second record of Therodamas from the Eastern Tropical Pacific and the first notice of the genus in Mexican waters. RESUMENSe describe detalladamente una especie nueva del género Therodamas Krøyer, 1863, uno de los tres géneros mesoparásitos de copépodos de la familia Ergasilidae. La descripción se basa en material recolectado en el robalo de aleta amarilla (Centropomus robalito Jordan & Gilbert, 1882) encontrado en un sistema lagunar de la costa mexicana del Pacífico Tropical Oriental. La nueva especie difiere de sus congéneres conocidos en la estructura general y proporciones del cuerpo y en detalles del armamento de las patas torácicas 1 y 4. Está más cercanamente relacionada con T.

Acusicola rochai n. sp. (Copepoda: Ergasilidae) parasitizing Anableps anableps (Anablepidae) from the Amazon Coast, with a key for Acusicola spp.

“…Morphometric data and ratios of body to appendage segment lengths have proven to be very useful across many families of cyclopoid copepods, including Ergasilidae (Suárez-Morales et al ., 2008; Oliveira et al ., 2021; Uyeno and Nagasawa, 2021; Paschoal et al ., 2022, 2023). Despite such an importance, the way that the information is described varies considerably in Acusicola , with numerous species lacking complete information about their measurements or proportions (Cressey and Collette, 1970; Amado and Rocha, 1996; El-Rashidy and Boxshall, 1999; Araújo and Boxshall, 2001; Santacruz et al ., 2020).…”

Two new species of Acusicola Cressey, 1970 (Copepoda:Cyclopoida: Ergasilidae) parasitic on the gills of two estuarine actinopterygians off Brazil

“…In contrast, there are three reports of ergasilids infesting Centropomidae fish: Ergasilus sp. on Centropomus undecimalis (Bloch) from Brazil, Ergasilus davidi Suárez-Morales & Santana-Piñeros, 2008 and Therodamas mexicanus Suárez-Morales, Santana-Piñeros & González-Solís, 2008 on Centropomus robalito Jordan & Gilbert from Mexico (Brian, 1927 ; Tavares & Luque, 2004 ; González-Solís et al, 2008 ; Suárez-Morales & Santana-Piñeros, 2008 ). Consequently, the present results, represent the first report of the genus Acusicola infesting fish of the families Lobotidae and Centropomidae in the world, suggesting that these two families include potential hosts for ergasilid copepods.…”