Schizoretepora calveti d’Hondt, 1975

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 : 8-10

Schizoretepora calveti d’Hondt, 1975

Fig. 4 , Table 1

Schizoretepora calveti d’Hondt, 1975: 581 .

Schizellozoon tesselatum – Calvet 1931: 108, pl. 2, fig. 32.

Material examined

Lectotype (designated here)

AÇORES • 3 fragments; 36º54.0 N, 25º09.5 W; 665–712 m; on gravel and pebbles; R/V Jean-Charcot Biaçores 1971 exped., st. 230; MNHN-IB- 2008 -7565.

Description

Colony erect and delicate, arborescent, dichotomously branched, vinculariform (never fenestrate) ( Fig. 4A ). Frontal faces bearing autozooids, abfrontal faces consisting of sheets of kenozooids. Branches thin, with two alternate series of autozooids.

Autozooids longer than wide, separated by distinct sutures. Branches biseriate, arranged in two alternating series of zooids (young apical branches), or triseriate quincuncially arranged (older basal branches). Frontal shield surface rippled, with meandering reliefs ( Fig. 4A ).

Primary orifice obscured by a tubular peristome, only its proximal side being visible through the spiramen. Proximal border provided with sharp, flat condyles drawing a U-shaped shallow sinus; distal border not observed ( Fig. 4B ).

Peristome well-developed. In young zooids it grows as two lobes, slightly widening at its free edge, embodying 6–8 spiniform processes on each side and converging at the anterior end ( Fig. 4B, E ), but remaining cut by large circular spiramen, shaped like ace of spades ( Fig. 4 A–B, E); in older zooids, distal end of lobes appear just denticulate and spiramen disappears ( Fig. 4D ).

One to three very large acute avicularia (usually paired), placed over large cystid in middle of frontal shield (when single) on both sides of aperture (when paired), mostly directed proximally, but sometimes distally ( Fig. 4E ). Rostrum acute and distally hooked, with stout bar without columella. One round pore on each side of cystid, 2 to 4 for entire frontal.

The ovicell in the type material (incompletely developed?) is hyperstomial, resting distally on adjacent zooid frontal shield, longer than wide; cut by large frontal fissure, broader at its distal end, smooth and imperforate, non-cleithral ( Fig. 4A, E ).

Abfrontal side consisting of sheets of irregular kenozooids separated by raised sutures; surface rippled, with numerous avicularia of two types: one similar to those on frontal, large and acute, 1–3 per kenozooid, becoming occluded by secondary calcification; and small elliptical avicularia rarely present (might be the anterior part of the large avicularia from which distal end has been occluded by calcification) ( Fig. 4F ).

Schizoretepora calveti is a deep-water species that has only been reported from the Azores archipelago, 599–712 m deep.

Remarks

This species was first figured by Calvet (1931) and considered as a variety of Schizellozoon tessellatum . D’Hondt (1975) noticed the differences in the material dredged by the Jean-Charcot during the Biaçores mission and that figured by Calvet (1931). After comparison with the type material sent by the British Museum he erected a new species: Schizoretepora calveti . D’Hondt (1975) did not designate a lectotype from his material; therefore, we formally designate here as type material the specimen MNHN-IB-2008-7565.

Looking at the abfrontal avicularia, this species resembles the Mediterranean species Reteporella pelecanus ( López de la Cuadra & García Gómez, 2001) . However, the latter species is a true Reteporella Busk, 1884 , possessing frontal labial avicularia and ovicells with an elongate median fissure not observed in the genus Schizoretepora . Nonetheless, the aspect of the frontal side with the circular spiramen and long peristome makes S. calveti unmistakable.

Figures

Fig. 4. Schizoretepora calveti d’Hondt, 1975, lectotype (MNHN-IB-2008-7565). A. Colony view. B. Detail of aperture and avicularia. C. Young autozooids and avicularia in frontal view. D. Older autozooids and avicularia in frontal view. E. Ovicellate zooids. F. Abfrontal view with avicularia.

Tables

Table 1. Measurements of Schizoretepora calveti d’Hondt, 1975.

	N	MEAN	SD	MIN	MAX
AzL	18	970	84	750	1097
AzW	18	568	116	396	746
ApL	22	210	36	160	289
ApW	22	180	30	124	242
VAL	40	329	53	227	440
VAW	40	117	35	76	219
AbAL	2	121	5	118	125
AbAW	2	66	7	61	71
AbVL	21	276	22	228	309
AbVW	21	87	9	71	106
OVL	4	269	14	258	289
OVW	4	223	19	197	241
Np	12	4	1	2	4
Np_Ab	10	3	1	2	5