Exechonella similis Caceres-Chamizo, Sanner, Tilbrook & Ostrovsky 2017
- Dataset
- Taxonomy and diversity of coelobite bryozoans from drift coral cobbles on Co To Island, northern Vietnam
- Rank
- SPECIES
Classification
- kingdom
- Animalia
- phylum
- Bryozoa
- class
- Gymnolaemata
- order
- Cheilostomatida
- family
- Exechonellidae
- genus
- Exechonella
- species
- Exechonella similis
description
(Fig. 6 E, F)
description
Measurements. AzL, 0.78 – 1.09 (0.930 ± 0.094); AzW, 0.52 – 0.80 (0.670 ± 0.074) (n = 15, 1). OrL, 0.18 – 0.21 (0.198 ± 0.012); OrW, 0.19 – 0.21 (0.203 ± 0.006) (n = 7, 1). Description. Colony encrusting, unilaminar, sheet-like. Zooids large, hexagonal, delineated by groove. Frontal shield convex, with minute areolae; perforated with 19 – 36 (29.7 ± 4.0; n = 13) foramina, each with smooth, raised rim. Orifice on average about as wide as long; with low, rounded condyles slightly proximal to middle; poster as wide as anter or nearly so, rounded-quadrate. Raised peristome surrounding orifice, slightly flared, smooth inside, pustulose outside, not obscuring orifice; often with low, blunt projection on proximal rim. Lateral-most foramen on one or both sides larger than rest, converted to avicularium, scarcely differentiated externally from other foramina. Oral spines, ooecia lacking.
discussion
Remarks. Cáceres-Chamizo et al. (2017) described this species in detail, with excellent illustrations. Average zooid size at Co To (AzL × AzW, 0.93 × 0.67 mm) is larger than presented in the original description (0.78 × 0.62 mm), but the number of frontal foramina is similar (19 – 36 at Co To vs 21 – 36 originally described). The original description states that the orifice is wider than long, but this is scarcely reflected in the accompanying measurements (OrL × OrW, 0.19 × 0.20 mm), and not at all at Co To (0.20 × 0.20 mm).
distribution
Distribution. The type locality is Lizard Island, Great Barrier Reef; this species is also known from Vanuatu (Cáceres-Chamizo et al. 2017). The previously known latitudinal range was 14 – 15 ° S; the Co To record extends the range northward nearly to 21 ° N.
materials_examined
Material examined. VNMN- 0226 (CT- 24), on SEM stub.