Chaperia taylori, Ramalho, Laís V. & Calliari, Lauro, 2015

Ramalho, Laís V. & Calliari, Lauro, 2015, Bryozoans from Rio Grande do Sul Continental Shelf, Southern Brazil, Zootaxa 3955 (4), pp. 569-587 : 571-572

Chaperia taylori sp. nov.

( Fig. 2 A–B)

Material examined. Parcel do Carpinteiro, Holotype: MNRJ-1163, am25 station 2, 32°09.173’S, 51°28.099’W, 0 7 Aug 2009; Paratype: MNRJ-1164, am 25 station 1, 32°09.513’S, 51°28.013’W, 0 7 Aug 2009; MNRJ-1165, MNRJ-1185, am09 pc3, 32°14.605’S, 51°43.991’W, 22 meters depth, 28 September 2009; MNRJ-1186, am22 parcel 1, 32°13.716’S, 51°46.101’W, 21 meters depth, 0 2 April 2009; MNRJ-1187, am 20, 32°30.086’S, 51°34.000’W, 40 meters depth; MNRJ-1188, am28 point 1, 32°10.086’S, 51°28.269’W, 28 August 2009; MNRJ- 1189, am30 station 0 1, 32°14.300’S, 51°46.630’W, 25 meters depth; MNRJ-1190, am12, 32°16.724’S, 51°47.111’W, 25 meters depth; MNRJ-1229, Am24 station 2, 32°09.406’S, 51°28.318’W, 31 July 2009.

Diagnosis. Colony growing around organic substrata; autozooids hexagonal with six distal spines, opesia longer than wide, occlusor laminae near the opesial border; frontal wall short, smooth and flat; distal wall with several spread pores not in the rosette plates.

Description. Colony fragments well calcified which grow around organic substrata ( Fig. 2 A).

Autozooids hexagonal (484–625 (567) µm long x 453–625 (512) µm wide) with rounded distal region, disposed in quincunx ( Fig. 2 A). Frontal cryptocystal wall short, smooth to lightly crenulated, and flat. Opesia oval, longer than wide (281–344 (317) µm long x 250–297 (277) µm wide), occupying more than half of the frontal surface ( Fig. 2 B). On the distal border there are usually six spines, rarely seven, disposed in line. Only spine scars are present and they suggest that the most distal spines are narrower and the most proximal spines do not reach the midline of the opesia border ( Fig. 2 A–B). Distal wall (inner) with numerous spread pores not included in the rosette plates ( Fig. 2 B). Two occlusor laminae developed, obliquely located on each side inside and very near the opesia border ( Fig. 2 A–B).

Avicularia not observed.

Oecium not observed.

Etymology. The name taylori is in homage to Dr. Paul D. Taylor from the Natural History Museum (London) who has contributed to studies about the Brazilian bryozoan fauna.

Geographic distribution. Rio Grande do Sul state - Parcel do Carpinteiro (present study).

Remarks. Almost twenty species of this genus are known, seven of them are recorded in the South Atlantic: Chaperia acanthina (Lamouroux, 1824) , Chaperia brasiliensis Vieira et al., 2010 , C. capensis (Busk, 1884) , C. familiaris Hayward & Cook, 1983 , C. laticella Canu, 1908 , C. polygonia (Kluge, 1914) , and C. septispina Florence et al., 2007 .

All of these species have opesia that are wider than long, differing from Chaperia taylori sp. nov., which has opesia longer than wide. Besides this C. acanthina has four or five distal spines, a longer cryptocyst, shorter and wider opesia (220–260 µm long x 280–300 µm wide); C. brasiliensis has more distal spines (7–11), shorter opesia (236 µm long x 265 µm wide); C. capensis has only two distal spines, opesia occupying more than 60% of the total front length; in C. familiaris the two most proximal distolateral spines and the occlusor lamina are nearer the distal region; C. laticella has smaller opesia (210 µm long x 250 µm wide), a convex, granulose and more developed cryptocyst; C. septispina has 5–7 distal spines, a shorter cryptocyst, occlusor laminae farther away from the opesium border, originating distally and reaching the proximal edge of the opesium.

Chaperia polygonia is the species most similar to Chaperia taylori , but besides the longer than wide opesium, it has a shorter and more crenulated frontal cryptocystal wall, occlusor laminae that are more robust and farther away of the opesium border, and two distal multiporous rosette plates. Based on these observations we believe that Chaperia taylori is a new species. López Gappa & Lichtschein (1988) recorded C. acanthina ( var. polygonia Kluge, 1914 ) for northern Argentina. These specimens may prove to be conspecific with C. taylori sp. nov.

Figures

FIGURE 2. Chaperia taylori sp. nov. (MNRJ- 1163). A, colony fragment; B, close-up of autozooids, showing the short cryptocyst, spine bases, opesiae, occlusor laminae, and numerous communication pores in the inner transverse walls. Scalebars: A, 500 µm; B, 100 µm.