Integripelta Gordon, Mawatari, and Kajihara, 2002

Grischenko, Andrei V., Dick, Matthew H. & Mawatari, Shunsuke F., 2007, Diversity and taxonomy of intertidal Bryozoa (Cheilostomata) at Akkeshi Bay, Hokkaido, Japan, Journal of Natural History 41 (17 - 20), pp. 1047-1161 : 1095-1097

Genus Integripelta Gordon, Mawatari, and Kajihara, 2002 Integripelta novella Gordon, Mawatari, and Kajihara, 2002

( Figure 18 ) Integripelta novella Gordon, Mawatari, and Kajihara 2002, p 205 , Figure 2A, B .

Material examined

DIN, six intact colonies detached from rock (NHM 2006.2.27.53). Additional material: 17 specimens.

Description

Colony unilaminar, encrusting, coherent, forming more or less circular patches with meandering borders, up to 3.5 cm in maximum dimension, dark red or pink when alive. Zooids ( Figure 18A–D ) roughly hexagonal or irregular, tapering proximally, rounded distally, widest just proximal to orifice, 0.45–0.70 mm long (0.58¡ 0.07 mm), 0.35– 0.49 mm wide (0.41¡ 0.04 mm), closely appressed, delineated by a shallow groove and suture line. Frontal wall gymnocystal, smooth-surfaced, slightly convex, mostly without fenestrae, but with a flat, strap-like carina running from proximal zooidal margin nearly to orifice, delineated by sharp borders, sometimes with a slit or foramen in proximal midline; some zooids with low, broad umbo proximal to orifice, occasionally occupying most of frontal wall. Autozooidal orifice hat-shaped, wider than long, 0.16–0.21 mm long (0.19¡ 0.01 mm), 0.23–0.29 mm wide (0.26¡ 0.02 mm), anter semicircular, with sharp indentations in proximolateral corners; proximal rim of poster gently concave, sometimes straight; peristome lacking. Lateral excavations of gymnocyst well developed, extending proximally from orificial indentations on one or both sides for a distance of up to half of zooid length. Zooids dimorphic; orifice of maternal zooids somewhat larger and higherarched than that of autozooids, though overlapping in size, 0.19–0.23 mm long (0.21¡ 0.01 mm), 0.25–0.32 mm wide (0.29¡ 0.02 mm). Kenozooidal ooecium ( Figure 18C, D ) caplike, flanked distally by a circular, triangular, or transversely crescentic foramen that varies considerably in size. Interzooidal communications via row of uniporous septula along each lateral wall. Spines and avicularia lacking. Ancestrula not observed.

Remarks

There are some small differences between our material and that from Kamekawa , Hokkaido, the type locality ( Gordon et al. 2002). In specimens from Akkeshi, zooids are slightly larger; the ooecial fenestra tends to be larger and more variably shaped; some zooids have a moderately developed frontal umbo; and the strap-like frontal carina can have a slit or fenestra at the proximal end. Our observations add to the range of variation known for this species .

Distribution

Hokkaido Island , Japan. This species was originally described from a tidal flat at Kamekawa (43 ° 039N, 140 ° 359E) on the Sea of Japan side of Hokkaido; the record at Akkeshi extends the known range to the Pacific side.

Figures

Figure 2. Dendrogram (below) showing similarity of sampling localities based on species presence/absence, and a map (above) showing the geographical distribution of three groups of sampling localities (circled) that are less than 70% similar in species composition between groups.

Figure 18. Integripelta novella Gordon, Mawatari, and Kajihara, 2002. NHM 2006.2.27.53. (A) General view of colony fragment; (B) immature zooids; (C) maternal zooids showing distal kenozooidal chambers possessing triangular, oval, and crescentic foramens; (D) close up of maternal zooids with foramen varying in size and form. Scale bars: 0.5 mm.