Schizoretepora sp. nov.?, Gregory, 1893

Madurell, Teresa, Jones, Mary Spencer & Zabala, Mikel, 2019, Revision of the Genus Schizoretepora (Bryozoa, Cheilostomatida) from the Atlantic-Mediterranean region, European Journal of Taxonomy 536, pp. 1-33 : 25-27

Schizoretepora sp. nov.? (= S. imperati sensu O’Donoghue & de Watteville 1939 )

Fig. 11 , Table 6

Non Retepora imperati – O’Donoghue & de Watteville 1939: 25–26.

Material examined

EGYPT • 1 colony; Mediterranean Sea, Alexandria; coll. O’Donoghue; labelled Retepora imperati ; NHMUK 1963.9 .4.12 .

Description

Colony erect, regularly fenestrate (reteporiform); frontal faces bearing autozooids, abfrontal faces consisting of sheets of kenozooids. Trabeculae with 2–6 longitudinal rows of autozooids arranged quincuncially. Fenestrae oval, 1–2 times as wide as trabeculae ( Fig. 11A, E ).

Autozooids longer than wide, convex, separated by distinct raised sutures. Frontal shield notably nodular, with 2–5 conspicuous areolae ( Fig. 11 C–D).

Primary orifice semi-elliptical, longer than wide, distal rim with 18 blunt, triangular denticles, proximal border with U-shaped sinus (wider than long) framed by two acute denticles that form a gutter on the proximal peristomial rim and flanked by smooth condyles, sloping towards the edges of the sinus ( Fig. 11B ).

Peristome relatively low, allowing most of the primary orifice features to be observed, with continuous proximal peristomial rim ( Fig. 11B ). Two oral spines, articulated, fragile and easily broken; only their bases remaining in older zooids ( Fig. 11D ). Although no club-like spines have been observed, there are differences in the diameter of their basis, supporting the possibility of their being present.

Giant avicularia on large cystid (with 2 pores) and very conspicuous; placed in different level of frontal and directed proximally or laterally; triangular, with straight borders and a hooked tip ( Fig. 11D ).

Ovicells were not observed.

Abfrontal convex and notably rugose, with large polygonal kenozooids separated by raised sutures and 1–3 pores ( Fig. 11E ). Abfrontal avicularia always triangular, with straight margins, hooked, variable in number but occasionally very numerous, of two different sizes, larger ones at basis of fenestrae; with slender crossbar, wide triangular lacuna and without columella ( Fig. 11F ).

Remarks

This specimen seems closely related to S. imperati , with a similar general shape, a relatively low peristome, an orifice, spines and frontal as well as abfrontal avicularia. Nevertheless, there are subtle differences in the appearance: the surface is more nodular and the giant avicularia are somehow different, with straight or slightly convex margins and a more acute profile (VAL/VAW> 2). The most remarkable differences, however, are in the biometric analysis ( Fig. 3 ), with it being smaller than the rest of species studied.

The rugose aspect of the frontal is reminiscent that of S. aviculifera , but it differs in the lack of frontal adventitious, almond-like avicularia.

O’Donoghue & de Watteville (1939) identified this species as Retepora imperati , though expressing doubts about the number of existing species of Retepora at that time. They already pointed out the difficulties in identifying specimens of Reteporidae , taking into account the ontogenetic differences, age of colony and differential criteria used by each author.

Overall, the little existing material, the lack of an ovicell in the examined specimen, and the sole location (Alexandria; south-eastern corner of the Mediterranean) renders the status of this possible new species dubious.

Figures

Fig. 11. Schizoretepora sp. nov. (= S. imperati sensu O’Donoghue & de Watteville 1939), from Schizoretepora imperati, coll. O’Donoghue (NHMUK 1963.9.4.12). A. Colony view. B. Primary orifice showing distal denticles and proximal condyles. C. Autozooids with giant avicularia. D. Large vicarious avicularia on cystid. E. Abfrontal view. F. Detail of abfrontal avicularium and rugose surface.

Fig. 3. Principal component analysis (PCA) biplot based on metric characters of the species Schizoretepora aviculifera (Canu & Bassler, 1930), S. granulosa (Canu & Bassler, 1930), S. hassi Harmelin, Bitar & Zibrowius, 2007, S. imperati (Busk, 1884), S. imperati sensu O’Donoghue & de Watteville 1939, S. imperati of other authors, S. longisetae (Canu & Bassler, 1928) and S. pungens (Canu & Bassler, 1925).

Tables

Table 6. Measurements of Schizoretepora sp. nov.? (= S. imperati sensu O’Donoghue & de Watteville 1939).

	N	MEAN	SD	MIN	MAX
FL	9	1056	178	825	1335
FW	14	458	64	335	542
TW	24	493	87	369	686
AzL	30	357	35	301	450
AzW	24	258	36	200	350
OL	32	92	8	77	101
OW	41	82	6	69	92
ApL	15	92	6	80	102
ApW	10	89	7	79	98
VAL	19	183	26	134	227
VAW	24	74	16	44	99
AbAL	21	151	29	89	199
AbAW	20	56	13	38	84
AbVL	13	277	24	223	300
AbVW	11	95	12	80	115
Ns	20	2	-	2	3
Np	28	4	1	2	5
Np_Ab	30	2	1	1	3