Renicola

Hechinger, Ryan F., 2019, Guide to the trematodes (Platyhelminthes) that infect the California horn snail (Cerithideopsis californica: Potamididae: Gastropoda) as first intermediate host, Zootaxa 4711 (3), pp. 459-494 : 485-486

Renicola sp. “martini” (sensu Hechinger and Miura [2014])

(16. Rema; Figs. 1 , 65–70 )

Diagnosis: Parthenitae. Colony comprised of inactive sporocysts, densely concentrated to irregularly clustered in snail gonad region, with dispersion into digestive gland. Sporocysts translucent orange to white; ~ 100–800 µm long, spheroidal to slightly elongate (length:width up to ~4:1).

Cercaria . Body mostly opaque white; non-oculate; with oral sucker bearing a stylet (a xiphidiocercaria) and with ventral sucker; with tegumental spines over much of surface; with all penetration gland ducts opening at stylet; with a large Y-shaped excretory bladder, the arms of which wrap around sides of ventral sucker; body ~ 200 µm long, ~equal in length to tail; tail simple.

Cercaria behavior: Fresh, emerged cercariae remain in water column, swim ~continuously, lashing tail back and forth.

Similar species: Rema is most readily distinguished from Repo [17] by the cercariae having tegumental spines and by the penetration gland duct arrangement.

Remarks: Hechinger and Miura (2014) described the sporocysts and cercariae, and provided COI and ITS1 DNA sequence data.

This species was not included in Martin (1972), but likely corresponds to “ Cercaria cerithidia 23” of Hunter (1942). This species, along with Renicola sp. “polychaetophila”, was previously referred to as “large xiphidiocercaria” in some ecological and evolutionary research (e.g., Hechinger et al. 2007; Kuris 1990).

Mature, ripe colonies comprise ~20% the soft-tissue weight of an infected snail (summer-time estimate derived from information on “Lgxi” in [ Hechinger et al. 2009]).

Nadakal (1960b) presents information on the pigments of the sporocysts and cercariae of this species (seemingly pooled with Renicola sp. “polychaetophila”) as his “Y-bladder cercaria”.

Figures

FIGURE 1. General characteristics of the parthenitae and cercariae of the trematodes infecting Cerithideopsis californica as first intermediate host. Species numbers and codes follow Table 1 and species accounts. Cercariae are all to scale, with additional magnified views of six small species (indicated by dashed lines). Note the oral stylets (presented in right lateral view) for Pruc and Smmi. Parthenitae are not to scale. Scale bars consistently indicate 100 µm.

FIGURES 65–70. Renicola sp. “martini” (Rema). 65, Overview of a colony in a freshly deshelled, infected horn snail in sea water. Arrow indicates the colony, which is localized in the gonadal region with infiltration of the digestive gland. Scale bar = 1 cm. Photo from Hechinger and Miura (2014). 66, Close-up of part of a slightly teased apart colony from a freshly dissected horn snail. Individual sporocysts are discernable. Scale bar = 1 mm. 67, Sporocysts, live, with developing cercariae, under heavy coverslip pressure. Note the paletot surrounding the sporocyst tegument. Scale bar = 200 µm. 68, Cercaria, live, under coverslip pressure. Scale bar = 100 µm. 69, Cercaria, live, with no coverslip pressure, with tegumental spines visible. Scale bar = 100 µm. 70, Close-up of cercaria oral sucker, stylet visible, under heavy coverslip pressure, using phase contrast. Scale bar = 10 µm.