Lepralia unicornis Johnston

HAYWARD, PETER J. & McKINNEY, FRANK K., 2002, Northern Adriatic Bryozoa From The Vicinity Of Rovinj, Croatia, Bulletin of the American Museum of Natural History 2002 (270), pp. 1-139 : 67-72

Lepralia unicornis Johnston , in Wood, 1844: 19. Schizoporella unicornis Hincks, 1877: 320 . Hay­

ward and Ryland, 1999: 220.

DESCRIPTION (AMNH 961): Colony encrusting, multiserial, unilaminar to multilaminar, developing extensive sheets. Autozooids rectangular to irregularly polygonal, strongly convex, separated by deep grooves. Primary orifice slightly wider than long, with a deep V­shaped sinus occupying about half width of proximal border; condyles small but distinctive, with acute upturned corners. No spines. Frontal shield with conspicuous epitheca, glistening in dried material; densely perforated by numerous small pores. Adventitious avicularia lateral to orifice, single or paired, situated adjacent to sinus; cystid swollen, rostrum acute to frontal plane, distolaterally directed, supporting a triangular mandible. Ovicell hyperstomial, globose; imperforate centrally, but developing a reticulate secondary calcification which appears porous; small pores present marginally, associated with conspicuous basal fluting. Ancestrula oval, tatiform, about half size of normal autozooids, at least five spines around distal end of opesia, producing single distal bud.

DISTRIBUTION: Schizoporella unicornis is distributed in the northeast Atlantic region from western Norway to the western Mediterranean, and does not appear to have been reported previously from the Adriatic. Around the British Isles it is common in littoral and shallow sublittoral habitats, especially among kelp holdfasts and on the undersides of boulders.

MEASUREMENTS (SKELETAL): AL 119 ± 14 µm, 94–134 (2, 8), AW 90 ± 14, 73–111 (2, 8), DO, 370 ± 70, 250–445 (2, 20), OL 102 ± 9, 85–119, 2, 21), OW 104 ± 6, 98–111 (2, 20), OvL 259 ± 25, 218–3–19 (2, 14), OvW 282 ± 16, 264–321 (2, 14), SL 27 ± 6, 17–38 (2, 21), SW 49 ± 7, 33–62 (2, 21), ZL 488 ± 36, 421–550 (2, 20), ZW 327 ± 59, 244–428 (2, 20).

Schizoporella errata ( Waters, 1878) Figure 30F–I

Lepralia errata Waters, 1878: 11 .

Schizoporella errata: Hayward and Ryland, 1999: 212 .

DESCRIPTION (AMNH 962; CMRR 2244): Colonies purple­brown with orange growing margins, multilaminar predominantly through frontal budding, often substantial. Autozooids irregularly polygonal and extremely variable in both size and shape; orientation inconstant in multilaminar colonies. Orifice slightly longer than wide; the anter semielliptical, widest proximally; condyles short and rounded, lodged in proximolateral corners and rather inconspicuous; sinus a deep, symmetrical U­shape, occupying about half proximal width of orifice. No spines. Frontal shield convex, regularly and closely perforated by large, round pores, the intervening calcification thickening as sharp ridges. Avicularia sporadic, developed proximolaterally to the orifice, the rostrum sharply tapered, directed distolaterally. Ovicell globular, with scattered pores, calcification thickening and pores deepening in later ontogeny.

Tentacles light orange, 16–19; lophophores bell­shaped, radially symmetrical, slightly obliquely truncate bordering chimneys.

Embryos bright orange.

REMARKS: S. errata is a prolific fouling organism; it covers almost all the available hard human­constructed substrata in parts of the Rovinj harbor (locality 34) and the mussel­culture station in Lim Channel (locality 33). The structure in Rovinj harbor is exposed to vigorous hydrodynamic conditions, whereas the Lim Channel locality is protect­ ed, with very low kinetic energy conditions. Colony morphology at the harbor locality is massive, with irregular knobby surfaces and centimeter­wide, millimeter­high cavities in which sediment or other extraneous objects may be immured; colonies are more densely grown and lack such cavities at the musselculture station. At the mussel­culture station, two morphologies predominate: relatively smooth­surfaced multilaminar encrustations, and prolific, commonly hollow, erect branches. These differences in growth habits between the two localities parallel the morphologies that the species exhibits between high­energy and low­energy localities in the Ligurian Sea along the Italian coast ( Cocito et al., 2000). However, the hollow centers of colonies found by Cocito et al. were generally very narrow and reflect growth around soft­bodied erect organisms such as hydroids. This may also be a cause for the initiation of erect growth at the Lim Channel mussel­culture station, but extensive portions of the erect branches there have broad, open centers that house vagrant organisms such as polychaetes and decapods. Movement of the inhabitants is the apparent cause of maintenance of the large hollow centers as branches extend and divide distally.

DISTRIBUTION: This is a readily recognized, widely distributed, and common fouling species. It is common throughout the Mediterranean and flourishes on man­made substrata as a persistent and sometimes troublesome fouling organism. It is present in similar situations in warm temperate to subtropical waters worldwide, and is a vigorously invasive species. Gordon and Mawatari (1992) record its recent spread in New Zealand ports.

MEASUREMENTS (SKELETAL): AL 181 ± 8 µm, 173–195 (1, 10), AW 137 ± 15, 117– 164 (1, 10), DO 456 ± 85, 311–627 (2, 20), OL 124 ± 18, 103–151 (2, 20), OW 128 ± 10, 112–146 (2, 20), SL 29 ± 4, 22–36 (2, 20), SW 64 ± 5, 53–72 (2, 20), ZL 570 ± 48, 495–676 (2, 20), ZW 384 ± 78, 288–518 (2, 20). (POLYPIDE): IH 149 ± 82 µm, 40– 320 (4, 35), LDMn 578 ± 128, 360–780 (1, 33), LDMx 648 ± 150, 360–900 (4, 49), TLMn 527 ± 81, 400–720 (4, 35), TLMx 576 ± 131, 400–900 (4, 40).

Schizoporella dunkeri ( Reuss, 1848) Figure 31A–E

Cellepora dunkeri Reuss, 1848: 90 .

Schizoporella unicornis form longirostris Hincks, 1886: 266 .

Schizoporella longirostris: Gautier, 1962: 151 . Hayward and Ryland, 1979: 173 (part). Zabala, 1986: 489. Zabala and Maluquer, 1988: 133.

Schizoporella dunkeri: Hayward and Ryland, 1995: 39, 1999: 210 .

DESCRIPTION (AMNH 891, 963; CMRR 2245): Colonies orange, multiserial, unilaminar to multilaminar, developing extensive, spreading sheets. Autozooids large, rectangular to irregularly polygonal; convex, separated by distinct, narrow sutures. Primary orifice about as wide as long, proximal bor­ der with a narrow sinus medially, its sides often straight and in parallel, proximal extremity more or less rounded; condyles massive, faceted, prominent and emphasizing sinus. No oral spines; peristome developed as a thickened ridge distally and laterally in lat­ er ontogeny. Frontal shield finely granular, densely perforated by small round pores, bounded by thickened rims; a low median suboral umbo developing in later ontogeny. Avicularia characteristic: monomorphic, proximolateral to orifice, single or paired, generally distolaterally directed; broadest at the thickened crossbar, the rostrum abruptly narrowed distal to it and tapered to a thin, blunt tip; frequently>0.2 mm long; mandible slender, acuminate. Additional, larger avicularia may be budded elsewhere on autozooid frontal surface when frontal expansion of colony occurs. Ovicell recumbent on distally succeeding autozooid, globular and prominent, calcification and perforation uniform with that of the frontal shield, often developing a frontal umbo.

Tentacles light orange, 16–20; lophophores bell­shaped, radially symmetrical between chimneys, obliquely truncate and locally scalloped adjacent to chimneys; overlap between adjacent lophophores up to 200 µm.

Embryo color dark orange. Ancestrula and early astogeny first described by Friedl (1925).

REMARKS: The type specimen is a Miocene fossil from the Vienna basin. Hincks (1886) introduced the taxon longirostris as a variety of the north European species S. unicornis (Johnston in Wood) and as S. longirostris it was subsequently reported from all parts of the Mediterranean, and northwards to the Isles of Scilly. Hayward and Ryland (1995) finally established the synonymy of S. dunkeri (Reuss) and S. longirostris (Hincks) .

DISTRIBUTION: In addition to the Distribution cited above (Remarks), Schizoporella dunkeri is abundant throughout the Adriatic, in shallow detritic environments.

MEASUREMENTS (SKELETAL): AL 301 ± 45 µm, 204–395 (3, 30), AW 138 ± 26, 97–182 (3, 30), DO 609 ± 97, 390–790 (3, 30), OL 160 ± 11, 133–176 (3, 29), OW 136 ± 13, 110–162 (3, 29), OvL 301 ± 19, 282–319 (1, 3), OvW 358 ± 23, 332–372 (1, 3), SL 42 ± 8, 31–53 (2, 9), SW 26 ± 8, 19–39 (2, 9), ZL 739 ± 69, 599–827 (3, 28), ZW 644 ± 94, 489–813 (3, 28). (POLYPIDE): IH 234 ± 59 µm, 140–350 (3, 20), LDMn 808 ± 100, 620–1000 (4, 39), LDMx 876 ± 116, 620–1200 (4, 43), MD 37 ± 4, 30–45 (3, 32), TLMn 718 ± 63, 600–850 (3, 12), TLMx884 ± 187, 680–1280 (4, 19).

Schizoporella magnifica Hincks, 1886 Figure 31F–J

Schizoporella magnifica Hincks, 1886: 268 . Zabala, 1986: 491. Zabala and Maluquer, 1988: 133. Hayward and Ryland, 1999: 216.

DESCRIPTION (AMNH 964, 965; CMRR 2246): Colonies cream­colored, encrusting, multiserial, unilaminar to multilaminar. Autozooids hexagonal to irregularly polygonal, convex, separated by distinct grooves. Primary orifice longer than wide, sinus a narrow, U­shaped slit equivalent to one­third length of anter, occupying about half proximal width; condyles rounded, faceted and conspicuous. Oral spines generally absent except in earliest colony astogeny, decreasing in number distally from three or four in zooids budded from ancestrula; no peristome. Frontal shield thick, tuberculate, densely perforated by small round pores. Ancestrula finely perforate, with eight oral spines around large D­shaped orifice, with straight proximal margin; orifice wider than long, maximum width at about midlength. Avicularia paired (rarely, single), situated lateral to orifice, usually distal to the sinus, some autozooids with an additional distolaterally directed adventitious avicularium proximal to orifice; cystid rounded, prominent, rostrum narrowly triangular, acute to frontal plane, directed distally or slightly distolaterally; crossbar slender, complete. Ovicell recumbent on frontal shield of distally succeeding autozooid, elongate oval, domed and prominent; texture and perforation similar to that of frontal shield, but a median apical area imperforate, and often developed as a longitudinal ridge or umbo.

DISTRIBUTION: This species is widespread and common throughout the Mediterranean and reaches its northern limit off the southwest British Isles.

MEASUREMENTS (SKELETAL): AL 161 ± 19 µm, 131–194 (2, 20), AW 109 ± 15, 90–144 (2, 20), DO 436 ± 52, 325–575 (2, 20), OL 126 ± 9, 108–145 (2, 20), OW 97 ± 9, 74– 111 (2, 20), OvL 380 ± 28, 334–446 (2, 20), OvW 304 ± 27, 243–334 (2, 20), SL 35 ± 6, 25–45 (2, 20), SW 24 ± 4, 15–32 (2, 20), ZL 540 ± 36, 494–641 (2, 20), ZW 389 ± 31, 330–442 (2, 20).

Schizoporella cf. S. tetragona ( Reuss, 1848) Figure 32A–D

Figures

Fig. 30. A–E. Schizoporella unicornis (AMNH 961). A. general aspect (0.5 mm). B. Autozooid (0.1 mm). C. Maternal zooid with ovicell (0.1 mm). D. Autozooidal orifice (0.05 mm). E. Broken ancestrula (bottom) and first­budded autozooid (0.1 mm). F–I. Schizomavella errata (AMNH 962). F. General aspect of region with frontally budded autozooids (0.5 mm). G. Autozooid (left) and (right) kenozooid (0.1 mm). H. Maternal zooid with ovicell (0.1 mm). I. Autozooidal orifice (0.05 mm).

Fig. 31. A–E. Schizoporella dunkeri. A. General aspect (AMNH 891; 0.5 mm). B. Autozooid with large adventitious avicularium adjacent to orifice (AMNH 891; 0.1 mm). C. Untreated specimen with mandibles and polypide rudiment preserved in avicularia (AMNH 963; 0.1 mm). D. Maternal zooid with ovicell (AMNH 891; 0.1 mm). E. Autozooidal orifice (AMNH 963; 0.05 mm). F–J. Schizoporella magnifica. F. General aspect (AMNH 964; 0.5 mm). G. Autozooid (AMNH 964; 0.1 mm). H. Maternal zooid with ovicell (AMNH 964; 0.1 mm). I. Autozooidal orifice (AMNH 964; 0.05 mm). J. Ancestrula (lower left) and early autozooids (AMNH 965; 0.1 mm).

Fig. 32. A–D. Schizoporella cf. S. tetragona (AMNH 966). A. General aspect (0.5 mm). B. Autozooid (0.1 mm). C. Maternal zooid with ovicell (0.1 mm). D. Autozooidal orifice (0.05 mm). E–I. Escharina vulgaris. E. General aspect (AMNH 967; 0.5 mm). F. Autozooid (AMNH 967; 0.1 mm). G. Untreated autozooids with setae­like mandibles of avicularia (type specimen of Lepralia botterii, UIIZ 217; 0.1 mm). H. Oblique view of autozooidal orifice (AMNH 967; 0.05 mm). I. Ancestrula (lower right) and early autozooids (AMNH 947; 0.1 mm).