Canda foliifera Harmer, 1926

Canda foliifera Harmer, 1926 View in CoL

Figure 10 View FIGURE 10

v. 1926 Canda foliifera Harmer , p. 386, pl. 26, figs. 21–23.

v. 2007 Canda foliifera Harmer ; Gluhak, Lewis and Popijac, p. 403, fig. 7A–D.

Figured material. PMC EDM-Collection

J.H.B.125a, sample 19071 ( Figure 10A–C, F View FIGURE 10 ) and sample 19200 ( Figure 10D–E View FIGURE 10 ); Core 19, Daidokutsu cave, Okinawa, Japan, Holocene.

Description. Colony erect with relatively narrow

(460–470 µm), rectilinear, biserial, keeled branches, triangular in cross-section, dichotomously branched; articulating nodes not observed.

Autozooids distinct, separated by shallow grooves,

rounded rectangular, elongate (mean ZL/ZW 1.84),

slightly asymmetrical, bent towards the external side of the branch, starting at zooidal mid-length, arranged alternately in two longitudinal series; three narrower autozooids present at bifurcations (187–231 µm wide). Frontal surface with minimal gymnocyst slightly wider in the proximal half of autozooids and around spines and the attachment base of the putative scutum; cryptocystal area outlined by a raised, undulating rim framing the proximal cryptocystal shelf and the opesia, forming a slightly prominent distal edge, and a mostly straight to slightly convex proximal edge, sometimes rounded, particularly in autozooids at bifurcations. Cryptocyst slightly depressed, occupying slightly less than half of the frontal surface (mean CryL/ZL 0.38), finely and densely granular, with granules around the opesia projecting into it, giving a spinose appearance, extensive proximally, very narrow laterally and distolaterally, absent distally. Opesia elongate, ovoidal with straight distal edge, occupying more than half of the frontal surface (mean OpL/ZL 0.59); a single spine present on the inner distolateral corner, 24–35 µm in diameter at the base, 0–1 spine on the outer distolateral corner, 13–24 µm in diameter at the base; an elliptical basal structure at the proximolateral edge, 50–90 µm long, interpreted as the base of a detached scutum; spines and putative base of scutum indenting the outlining rim. Avicularia absent. Ovicells not observed. Dorsal side occupied by vibracula with a long, curved, deep setal groove oriented distolaterally; a shallow sinuous median furrow corresponding to zooidal boundaries; a large, circular radicular pore, measuring 50–70 µm in diameter, placed proximally on each vibraculum on the outer side of the branch.

Measurements (µm). ZL 471±33, 419–530 (3, 15); ZW 255±14, 229–274 (3, 10); OpL 276±39, 205– 333 (3, 13); OpW 147±8, 134–158 (3, 10); CryL 178±19, 159–233 (3, 15); VibrL 261±18, 246–310 (2, 10); VibrW 177±12, 153–194 (2, 10).

Remarks. Canda foliifera is an extant species reported from various locations in the Indo-Pacific. Initially identified as Canda retiformis Pourtales, 1867 by Thornely (1905, 1912) in Zanzibar and the Seychelles and by Waters (1913) in Sri Lanka, these records were later synonymized by Harmer (1926) with his new species found at several Indonesian stations during the Siboga Expedition. More recently, it has been found in samples from Taiwan (Gluhak et al., 2007). The main features of C. foliifera are the extensive cryptocyst with a straight proximal edge, the lack of frontal avicularia, and a large, asymmetrical scutum (Gluhak et al., 2007). In our subfossil specimens, the scutum appears to be detached, but its presence can be inferred from the robust base observed on the proximolateral inner corner of the opesial rim ( Figure 10E View FIGURE 10 , arrowed). This structure closely resembles that illustrated by Gluhak et al. (2007, p. 403, figure 7C) in their Taiwanese material.