Two new species of dicyemid mesozoans (Dicyemida: Dicyemidae) from Octopus maya Voss & Solis-Ramirez (Octopodidae) off Yucatan, Mexico

Abstract

Two new dicyemid species are described from the endemic cephalopod Octopus maya Voss & Solis-Ramirez collected off Yucatan, Mexico. The renal sacs of 40 juvenile and adult octopuses from four localities were examined. Dicyema hochbergi n. sp. is a medium-sized species that reaches 2,245 µm in length. The vermiform stages consist of 18-24 peripheral cells, a conical calotte and the extension of the axial cell between the base and middle of the metapolar cells. Infusoriform embryos consist of 39 cells with urn cell containing one germinal cell, two nuclei and solid refringent bodies. Dicyema mexcayae n. sp. is a relatively small species that reaches 1,114 µm in length. The vermiform stages are constituted by 14-16 peripheral cells, an elongate calotte and the axial cell extending forward to the middle of the metapolar cells. The infusoriform embryos consist of 37 cells, two solid refringent bodies and urn cells with two nuclei each. The present study represents the first description of a dicyemid species from O. maya and increases the number of described species from Mexican waters to 11.

Progenesis in dicyemids

“…Gould, 1977;McNamara, 1997). In addition, Dicyema mexcayae from Octopus maya in the Gulf of Mexico has a small rhombogen that is the same size as the vermiform embryo (Castellanos-Martinez et al, 2016), the smallest of which starts to mature at 80 μm, whereas the largest vermiform embryo developing within the axial cell was as large as 147 μm. This suggests that the vermiform embryo matures into a rhombogen with little or no growth.…”

Fourteen New Species of Dicyemids (Phylum: Dicyemida) from Seven Species of Decapodiformes (Mollusca: Cephalopoda) in the Kumano Sea, Japan

“…To date, 135 dicyemid species have been described from cephalopod hosts distributed in a variety of geographical localities: the Okhotsk Sea, the Sea of Japan, western and eastern North Pacific Ocean, South Pacific Ocean, North Indian Ocean, the Mediterranean Sea, western and eastern North Atlantic Ocean, the Gulf of Mexico, and the Antarctic Ocean (Nouvel 1947;McConnaughy 1951;Hochberg 1990;Short 1991;Furuya 1999Furuya , 2018Furuya and Tsuneki 2003;Catalano 2013;Castellanos-Martinez et al 2016). Of more than 50 species recognized from 27 cephalopod hosts in Japanese waters, 50 nominal species have been described in just 18 hosts (Furuya 2016).…”

Dicyemids

“…Typically, two or three dicyemid species are found in individuals of each cephalopod species and most are host specific (Furuya 1999). Currently, about 140 dicyemid species have been recorded from cephalopod hosts distributed in a variety of geographical localities: the Okhotsk Sea, Japan Sea, western and eastern North Pacific Ocean, waters around New Zealand, North Indian Ocean, Mediterranean, western North and eastern Atlantic Ocean, Gulf of Mexico, and Antarctic Ocean (Catalano 2013;Castellanos-Martinez et al 2016;Furuya 1999;Furuya and Tsuneki 2003;Hochberg 1990;McConnaughey 1951;Short 1991). The dicyemids are heavily infecting the renal organs in their host cephalopods ( Fig.…”