Micropora erecta, Boonzaaier-Davids & Florence & Gibbons, 2020

Boonzaaier-Davids, Melissa K., Florence, Wayne K. & Gibbons, Mark J., 2020, Novel taxa of Cheilostomata Bryozoa discovered in the historical backlogs of the Iziko South African Museum, Zootaxa 4820 (1), pp. 105-133 : 112-113

? Micropora erecta n. sp.

( Fig. 4 A–F, Table 3)

zoobank.org/ 4FAFEA9A-B13D-4699-B4F4-B7889135D1AC

Material examined. Holotype: SAMC-A028821 (in ethanol), station AFR 866 (34°36.8’S, 19°16.4’E), Agulhas Bank , South Coast, South Africa, UCT Ecological Survey, dredge, depth 38 m, 9 January 1948 . Additional material: SAMC-A073536 (dry), FAL 79 ; SAMC-A073463 (in ethanol), FAL 503 ; SAMC-A073482 (in ethanol), FAL 504 ; SAMC-A077326 (in ethanol), FAL 818 ; SAMC-A029102 (in ethanol), WCD 11. Additional comparative material: Micropora similis , SAMC-A026418 (holotype), station SM 163 (33°04.6’S, 28°06.6’E), off East London, Southeast Coast, South Africa , RV Meiring Naude Survey , heavy dredge, depth 90 m, 26 May 1978 ; SAMC-A026525 , same station as above. Micropora latiavicula , SAMC-A028594 (holotype), Saldanha Bay (33°01’S, 17°59’E), West Coast, South Africa, collected by W. Florence, depth 15 m, 15 February 2001 .

Etymology. From the Latin, referring to the erect colony growth form.

Diagnosis. Colony erect, bilaminar. Autozooids with cryptocyst smooth centrally and granular along the margins with small pseudopores; opesiules paired, finely toothed. Opesia with raised proximal rim and indentations. Interzooidal avicularia present. Ovicell hyperstomial; ooecium granular, smooth proximally.

Description. Colony erect, forming broad, bilaminar branches, raising from an encrusting base; colour light brown to yellow in ethanol preserved material, creamy white in dried material. Autozooids elongate, rectangular, about 0.70 mm long by 0.30 mm wide, sometimes tapered proximally. Cryptocystal surface smooth centrally, granular along the zooidal margins, with 16–33 (N T = 10) circular, oval to irregularly shaped pseudopores of variable size; distolateral walls of autozooid forming a raised nodular rim below the opesia; rarely parts of the frontal shield unevenly raised by secondary calcification. Opesia wider than long, semicircular, with straight proximal border and paired opesiular indentations; paired opesiules finely toothed, placed proximal to the thickened orificial rim. No spines. Interzooidal avicularia present; crossbar complete, rostrum acute, directed obliquely distally. Ovicell hyperstomial, cleithral, with dimorphic opening; ooecium formed by the distal autozooid, with membranous ectooecium and calcified entooecium, partially covered by secondary calcification. In cleaned specimens, ooecium with granular surface, except for a narrow, smooth proximal border.

Remarks. Globally, there are 70 known Micropora Gray, 1848 species, of which nearly half are extinct (www. bryozoa.net, accessed 06 June 2020).? Micropora erecta n. sp. closely resembles M. angusta MacGillivray, 1887 , in the zooidal shape, the position of interzooidal avicularia and opesiules but it differs in having erect growth form and smooth cryptocyst centrally. Numerous other species (e.g. M. mawatarii Arakawa, 2016 , M. plana Arakawa, 2016 and M. rimulata Canu & Bassler, 1929 ) differ from? M. erecta n. sp. in having evenly granular frontal surfaces.

? Micropora erecta n. sp. was also compared to Micropora species found in the Indian Ocean. Micropora latiavicula Florence, Hayward & Gibbons, 2007 from South Africa is distinguished by its slender zooids, interzooidal avicularia with broad sloping rostra that are directed obliquely distally, deep and circular opesiules proximal to the orifice on either side, and accessory opesiule openings subjacent to the primary opesiules. Another species reported previously from South Africa, M. similis Hayward & Cook, 1983 , can be distinguished by the small distinct bosses adjacent to the opesia, slender autozooids and densely punctured cryptocyst ( Hayward & Cook 1983).? Micropora erecta n. sp. differs from both, because it lacks accessory opesiules, has a smooth frontal surface (though granular along the zooidal margins) and indentations at the proximal corners of the opesia ( Fig. 4C ).

This new species seemingly differs from typical Micropora species and other known genera in the family Microporidae Gray, 1848 , and is only tentatively assigned to Micropora based on the structure of the ovicell ( Ostrovsky 2013), semicircular orifice, paired opesiules and presence of interzooidal avicularia.

? Micropora erecta n. sp. was found from the Southwest Coast at Cape Peninsula to Agulhas Bank , including False Bay area , on the South Coast at 38–147 m depth .

Figures

FIGURE 4. A–F.?Micropora erecta n. sp. A. Group of autozooids (SAMC-A029102) (scale bar = 0.4 mm, magnified x35). B. Autozooids and interzooidal avicularia (SAMC-A029102) (scale bar = 0.2 mm, magnified x75). C. Close-up of the orifice, showing proximal indentations and thickened suboral margin (SAMC-A029102) (scale bar = 0.05 mm, magnified x500). D. Interzooidal avicularia (SAMC-A029102) (scale bar = 0.1 mm, magnified x150). E. Group of ovicelled and non-ovicelled zooids (SAMC-A028821) (scale bar = 0.4 mm, magnified x50). F. Ovicelled zooid (SAMC-A028821) (scale bar = 0.2 mm, magnified x150).