Exechonella safagaensis, Cáceres-Chamizo & Sanner & Tilbrook & Ostrovsky, 2017

Cáceres-Chamizo, Julia P., Sanner, Joann, Tilbrook, Kevin J. & Ostrovsky, Andrew N., 2017, Revision of the Recent species of Exechonella Canu & Bassler in Duvergier, 1924 and Actisecos Canu & Bassler, 1927 (Bryozoa, Cheilostomata): systematics, biogeography and evolutionary trends in skeletal morphology, Zootaxa 4305 (1), pp. 1-79 : 16-19

Exechonella safagaensis n. sp.

( Fig. 5 , Table 5)

? Lagenipora tuberculata: Waters 1909 , p. 172–173.? Exechonella tuberculata: Balavoine 1959 , p. 271, pl. 3, fig. 4.? Exechonella tuberculata: Powell 1969 , p. 358.

? Exechonella tuberculata: Dumont 1981 , p. 635.

? Lagenipora tuberculata: Thornely 1905 , p. 113.

? Lagenipora tuberculata: Thornely 1907 , p. 188.

? Lagenipora tuberculata: Thornely 1912 , p. 146.

Material examined. Holotype: DPUV 2013-0001-0001 , on dead coral Coscinaraea sp. Red Sea, the Northern Bay of Safaga , transect B 9, depth 38 m, 16 July 1987 . Paratypes: DPUV 2013-0001-0002 , on coral rubble, Porites sp. Red Sea, the Northern Bay of Safaga , transect B 7, depth 45 m, 15 November 1986 ; DPUV 2013-0001-0003 ¸ on coral Echinopora sp. Red Sea, the Northern Bay of Safaga , transect B 11, depth 40 m, 14 July 1987 ; DPUV 2013- 0001-0004 , on coral Coscinaraea sp. Red Sea, the Northern Bay of Safaga , transect B 9, depth 38 m, 16 July 1987 ; DPUV 2013-0001-0005 , on coral Echinopora sp. Red Sea, the Northern Bay of Safaga , transect B 11, depth 40 m, 14 July 1987 ; DPUV 2013-0001-0006 , on coral rubble. Red Sea, the Northern Bay of Safaga, west the Northern Bay of Safaga Island , transect A 5, depth 1–2 m, September 1992 ; DPUV 2013-0001-0007 , on coral rubble. Red Sea, the Northern Bay of Safaga , depth 14 m, 17 February 1992 ; DPUV 2013-0001-0008 , on coral rubble. Red Sea , the Northern Bay of Safaga, 24 February 1987 . Mounted on SEM stubs and coated with gold: DPUV 2013-0001 - 0 0 0 9, on coral rubble. Red Sea, the Northern Bay of Safaga , depth 25 m, 10 July 1987 ; DPUV 2013-0001-0010 , on coral rubble. Red Sea, the Northern Bay of Safaga, south of Ras Abu Soma , depth 1–20 m, September 1992 . Other material examined: IPUW 7020 , seven colony fragments on the pieces of coral Porites sp. Red Sea, the Northern Bay of Safaga , transect B 9, depth 38 m, 16 July 1987 ; IPUW 7021 , on coral Echinopora sp. Red Sea, the Northern Bay of Safaga , transect B 11, depth 40 m, 14 July 1987 ; IPUW 7022 , on bivalve shell. Red Sea , the Northern Bay of Safaga, Ras Abu Soma, 2 October 1992 ; IPUW 7023 (mounted on SEM stub and coated with gold), IPUW 7024, two colonies on coral rubble. Red Sea, Jeddah, coll. by Dr. A. Antonius in the late 1970’s (collection date not specified) . DPUV collection (non-numbered specimens mounted on SEM stubs and coated with gold): two small colonies, Red Sea, the Northern Bay of Safaga (further collecting data not specified); 3-zooid colony on bivalve shell, Red Sea , the Northern Bay of Safaga , south of Ras Abu Soma , depth 1‒20 m, September 1992 ; small colony, Red Sea, the Northern Bay of Safaga , station B 3/2, depth 4 m, sand between coral patches, 16 July 1987 ; ancestrula, on coral Alveopora viridis , Red Sea, the Northern Bay of Safaga , transect B 7, depth 45 m, 15 November 1986 .

Etymology. Named after the Northern Bay of Safaga, Red Sea, from where the holotype specimen was collected.

Description. Colonies encrusting, unilaminar, multiserial. Autozooids bottle-like: convex, oval-elongated, separated by deep grooves and pits in the ‘corners’ between zooids. Primary orifice oval, wider than long. Anter wall underlain by an inner lamina (only visible in oblique view) ending in distolateral condyles seen as narrow elongated plates slightly widening distally. ‘Pocket’ associated with a condyle has been detected in some zooids. Long tubular peristome is pustulose externally and with longitudinal grooves on its internal surface. Peristome rim is slightly flared, in some colonies with a variable number of small projections. Frontal shield pustulose, with 23– 46 (Safaga) and 30–58 (Jeddah) rounded or oval foramina. Lumen of each foramen has vertical, wide gymnocystal walls, often wrinkled, whereas an area around is a slightly elevated wide ring with an inner wall surface. In some zooids from one to ten foramina bear long conical and sharp frontal processes (spikes). Each process has mostly a gymnocystal surface with its edges merging on the back side of the spike (sometimes forming a conical ‘tube’), connected with corresponding gymnocystal walls of its foramen. Marginal pores small and rounded, with centrally perforated cuticular plate. The distalmost part of zooid below peristome can bear up to two rows of such pores. No avicularia. Adventitious kenozooids with 2‒5 pores, each having centrally perforated cuticular plate. Vertical zooidal walls narrow, represented by multiporous mural septula with communication pores arranged in 1–2 rows. Ancestrula autozooidal, with foramina sometimes as numerous as in regular autozooids.

Northern Bay of Safaga, Red Sea Jeddah, Red Sea Remarks. Our material from the Red Sea is strongly reminiscent of Exechonella ampullacea from Heron Island. The examination of its holotype allowed recognition of the following major similarities and differences, namely: (1) in both species autozooids of oval shape with tall and tubular peristome and a range of frontal foramina of 23–46 (Safaga), 30–58 (Jeddah) and 16–41 (Heron Island) (original description of E. ampullacea mentions 30– 44 foramina, but re-examination of the holotype showed autozooids with as few as 16 foramina); (2) presence of narrow elongated condyles in distolateral position; (3) similar zooidal size with length to width ranges of 667– 889×354–606 µm (Heron Island), 607–1160×351–733 µm (Safaga) and 560–900×480–600 µm (Jeddah). The difference is the total absence of the frontal pointed processes in the Heron Island material. In contrast, such processes are always found in the colonies from the Red Sea.

Our Red Sea specimens are superficially similar to E. tuberculata ( MacGillivray, 1883) that has been often mentioned in the Red Sea ( Waters 1909; Balavoine 1959; Powell 1969; Dumont 1981; Winston 1986 [based on Dumont’s paper]), Indian Ocean near Madagascar, Réunion and India ( Thornely 1905, 1907, 1912; Robertson 1921; d’Hondt 2016a, b) and from different localities in Indonesia, Philippines, Sri Lanka, New Guinea, Australia ( Canu & Bassler 1929; Harmer 1957; Scholz & Cusi 1991) and New Zealand ( Gordon 1984).

E. tuberculata was described (as Lagenipora ) by MacGillivray in 1883 from Port Phillips Heads, Australia. Cook and Bock (2004) examined the holotype of this species and additionally described and illustrated a small colony from the Bass Strait (figs 3b–d) (see above). The species is characterized by zooids with long tubular peristome and 16–27 foramina (Cook and Bock mentioned not more than 20 foramina in the description). Each foramen bears large thick blunt process only one side of which (faced to foraminal opening) is gymnocystal. Such processes are not so numerous in E. safagaensis n. sp., being also pointed and more slender. After examining a considerable amount of material from the Northern Bay of Safaga and Jeddah, however, we are certain that the local species of Exechonella , could be easily assigned to E. tuberculata by previous authors due to the presence of these spinous processes.

When Waters (1909, p. 172) reported E. tuberculata (as Lagenipora ) from the Sudanese Red Sea, he noted the presence of these projections and wrote that they “do not occur on all the pores and are not so large as in those from Australia.” This note spports our suggestions. Also, optical photo of the two-zooid specimen of ‘ E. tuberculata’ published by Balavoine (1959, pl. 3, fig. 4) shows a resemblance with our material. The remaining authors dealing with the Red Sea bryozoans only mentioned E. tuberculata in the species lists.

Distribution. Exechonella safagaensis n. sp. is only found in the Red Sea; in the Northern Bay of Safaga (western coast) and Jeddah (eastern coast).

Figures

FIGURE 5. Exechonella safagaensis n. sp. Red Sea (A ‒ C: paratype DPUV 2013 - 0001 - 0009, the Northern Bay of Safaga; D ‒ F: paratype DPUV 2013 - 0001 - 0010, the Northern Bay of Safaga; E, IPUW 7023, Jeddah). A, general view of the colony from above. Ancestrular zone is broken. B, central part of the same colony. C, lateral view of the peripheral part of the same colony showing non-damaged peristomes with flared edge and frontal processes associated with foramina. D, lateral view of the peripheral part of the colony showing non-damaged peristomes with rounded edge without spikes and lateral multiporous septula. E, primary orifice with condyles hardly visible (arrows). F, close-up of the frontal shield with foramina two of which bear pointed process. Scale bars: A = 1 mm; B ‒ E = 100 µm; F = 10 µm.