Schizoretepora imperati ( Busk, 1884 )

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 : 17-20

Schizoretepora imperati ( Busk, 1884)

Fig. 8 , Table 4

Retepora imperati Busk, 1884: 110 , pl. XXVI, fig 9.

Non Retepora imperati –Waters 1894: 262; 1925: 659.

Non Schizellozoon imperati – Canu & Bassler 1928: 49–50, pl. IV, fig. 10. — Barroso 1935: 378, fig. 6a–d.

Non Schizoretepora imperati – Gautier 1962: 235–236.

Material examined

Syntypes

CAPE VERDE ISLANDS • 1 colony; Porto Praya; 100–120 fathoms deep; Challenger exped. [ex Dundee museum collection]; labelled Retepora imperati ; NHMUK 1963.2 .12.202 • 1 colony; same collection data as for preceding; NHMUK 1934.2 .16.23 .

ALGERIA • 1 colony; Oran; [sent to A.M. Norman by A.W. Waters] labelled Retepora imperati ; NHMUK 1911.10.1.813 • 1 colony; same collection data as for preceeding but coll. Mr Alder; A.M. Norman leg.; labelled Retepora imperati ; NHMUK 1911.10.1.814 • 2 colonies, several fragments; same collection data as for preceding; coll. Canu; labelled Retepora imperati ; MNHN-IB- 2014-29 • 1 colony; same collection data as for preceding; coll. Calvet; labelled Retepora imperati ; MNHN-IB- 2008-6052 • 1 colony; same collection data as for preceding; MNHN-IB- 2008-982 • 1 colony; same collection data as for preceding; MNHN-IB- 2008-983.

ITALY • 1 colony; Sicily, Palermo; Marquis di Monterosto leg., coll. A.M. Norman; labelled Retepora imperati ; NHMUK 1911.10 .1.1374 .

MOROCCO • 2 colonies; st CX, 1926, R/V Vanneau exped.; coll. Canu; labelled Retepora imperati ; MNHN-IB- 2008-9955 • 1 colony; SW Alboran Sea, st. 1294; 3 Sep. 1958; R/V Calypso; coll. Gautier; labelled Retepora imperati ; MNHN-IB- 2008-11299.

Description

Colony erect, regularly fenestrate (reteporiform); frontal surfaces bearing autozooids, abfrontal faces consisting of sheets of kenozooids. Trabeculae with 2–4 longitudinal rows of autozooids arranged quincuncially. Fenestrae oval, longer than wide ( Fig. 8A ).

Autozooids ovoid, longer than wide, convex, separated by distinct raised sutures. Frontal shield smooth or finely rugose, with 2–4 areolae ( Fig. 8 C–D).

Primary orifice semi-elliptical, longer than wide, distal rim with 16–18 blunt, triangular denticles, proximal border with U-shaped sinus (wider than long) and flanked by smooth condyles, sloping towards the edges of the sinus ( Fig. 8B ).

Peristome thin, slightly raised on both sides of orifice ( Fig. 8C ). Autozooids with two oral spines (only the bases observed), one with thicker diameter ( Fig. 8B ). Giant avicularia on a large cystid (with 2 pores), in the middle of frontal plane, rostrum triangular with slightly concave margins and hooked tip, laterally directed, crossbar robust and without columella ( Fig. 8C ).

Ovicell typically globular, longer than wide, immersed with secondary calcification, surface smooth, imperforate, with large central fissure, widening at base, non-cleithral ( Fig. 8E ).

Abfrontal slightly granular, with large polygonal kenozooids separated by raised sutures. Two types of abfrontal avicularia, adventitious triangular, scattered around kenozooids, and giant avicularia typically located at base of fenestrae, triangular ( Fig. 8F ).

Remarks

Spines were not reported by Busk (1884) in the original description, but the study of his own material reveals the presence of the remaining holes. The giant abfrontal avicularium is rare in the material provided (syntypes); however, Busk (1884) already reported their presence, as did Waters (1895). Since no young or apical parts remain in the type material, it cannot be ascertained whether young zooids present the two triangular flaps characteristic of other nearer species (i.e., S. pungens , see Figs 9E , 10C ); thus, this difference could also be due to ontogenetic changes.

S. imperati (Busk) differs from S. pungens in:

– lacking oval adventitious avicularia both frontal and abfrontal

– the shape of abfrontal adventitious avicularia, triangular in S. imperati (Busk) ( Fig. 8F ) but oval or almond-shaped in S. pungens ( Fig. 10 E–F)

– in the shape of the peristome, thinner in S. imperati . Indeed, in the type material we did not observe the distinctively pointed lateral flaps characteristic of S. pungens ( Figs 9 C–D; 10C), though these were included in the original description ( Busk 1884), and it could be a character associated with young zooids

The abfrontal of S. imperati (Busk) is closer to that of S. aviculifera (as described here) as both have numerous triangular avicularia, but they differ on the rugosity of the surface ( Figs 7H , 8F ), being smoother in S. imperati (Busk) . They differ on the frontal face because of the presence of almond-like avicularia in S. aviculifera ( Fig. 7E ), always missing in S. imperati (Busk) ( Fig. 8 C–D).

Figures

Fig. 8. Schizoretepora imperati (Busk, 1884). A from Retepora imperati, syntype (NHMUK 1963.2.12.202); B–F from Retepora imperati, syntype (NHMUK 1934.2.16.23). A. Colony, frontal view. B. Primary orifice, detail. C–D. Ovicellated autozooids with giant avicularia. E. Detail of ovicellated autozooid with giant avicularia. F. Abfrontal view with triangular avicularians.

Fig. 9. Schizoretepora pungens (Canu & Bassler, 1925). A from specimen labelled as Schizellozoon longisetae, Gautier leg. (MNHN-IB-2008-11127); B, H from specimen labelled as Retepora imperati, coll. Canu (MNHN-IB-2014-29); C from specimen labelled as Schizellozoon longisetae (MNHN- IB-2008-14462); D from Schizoretepora pungens, holotype, coll. Canu (MNHN-IB-2014-20); E from Schizoretepora pungens (MNHN-IB-2008-14434); F from specimen labelled as Retepora imperati (MNHN-IB-2008-982); G from specimen labelled as Retepora imperati, coll Calvet (MNHN- IB-2008-6052). A. Young colony with spines. B. Primary orifice showing distal denticles, proximal condyles, sinus and smothered peristome. C. Young autozooids showing spines and acute peristomes. D. Old autozooids lacking spines and with smothered peristomes. E. Detailed view of articulated and carenated club-like spines. F. Adventitious triangular (upper side) and oval (bottom right) avicularians. G. Giant avicularium at basis of fenestra. H. Giant avicularia on large cystids showing crossbar without columella.

Fig. 10. Schizoretepora pungens (Canu & Bassler, 1925). A from Schizoretepora imperati, coll. Gautier (MNHN-IB-2008-11299); B, F from Schizoretepora pungens (MNHN-IB-2008-14434); C from Schizoretepora pungens, holotype, coll. Canu (MNHN-IB-2014-20); D from specimen labelled as Schizoretepora imperati (MNHN-IB-2008-9955); E, G from specimen labelled as Schizoretepora longisetae, coll. Canu (MNHN-IB-2014-19); H from Schizoretepora pungens (MNHN-IB-2008-14045). A–B. Two ovicell aspects in young colonies. C. Deeply immersed ovicells in older colonies. D. Abfrontal face showing rugose kenozooids separated by raised sutures. E. Abfrontal face showing two types of adventitious avicularia, both oval and almond-shaped. F. Abfrontal detail of giant avicularium at the basis of a fenestra and small oval avicularia. G. Aspect of spinose colony. H. Aspect of serrated colony.

Fig. 7. Schizoretepora aviculifera (Canu & Bassler, 1930). A–B, F–G from Schizellozoon aviculiferum, holotype, coll. Canu (MNHN-IB-2014-24); C from specimen labelled as Schizellozoon longisetae (MNHN-IB-2008-11127); D, H from Schizellozoon granulosum, syntype, coll. Canu (MNHN- IB-2014-21); E from Schizellozoon aviculiferum (MNHN-IB-2008-11126). A. Frontal colony view. B. Primary orifice detail. C. Apical view of colony (note the articulated and carenated spines). D. Old ovicellate colony. E. Detail of young autozooids showing ovicells in formation and adventitiuos avicularia (note the giant club-like spine). F. Ovicellate zooids. G. Abfrontal view with avicularia. H. Abfrontal view showing triangular avicularia.

Tables

Table 4. Measurements of Schizoretepora imperati (Busk, 1884).

	N	MEAN	SD	MIN	MAX
FL	16	1508	299	1082	1949
FW	25	703	167	350	1064
TW	44	627	131	389	907
Nz	19	3	1	2	5
AzL	30	471	53	326	594
AzW	25	323	36	271	408
OL	15	108	8	96	124
OW	14	86	5	78	98
ApL	23	135	13	111	162
ApW	28	104	9	87	126
VAL	12	183	22	160	232
VAW	20	109	17	71	136
OVL	20	200	55	140	321
OVW	13	168	35	130	261
AbAL	40	146	18	100	180
AbAW	41	67	10	45	90
Ns	28	2	0	2	2
Np	58	3	1	2	5
Np_Ab	36	5	3	1	12