Dendrobeania lichenoides Robertson, 1900

Dick, Matthew H., Grischenko, Andrei V. & Mawatari, Shunsuke F., 2005, Intertidal Bryozoa (Cheilostomata) of Ketchikan, Alaska, Journal of Natural History 39 (43), pp. 3687-3784 : 3717-3719

Dendrobeania lichenoides Robertson, 1900

( Figure 6E, F )

Flustra lichenoides Robertson 1900, p 322 , Plate 20, Figures 7, 7a , 8 .

Flustra lichenoides: Robertson 1905, p 291 , Plate 15, Figures 91, 92, Plate 16, Figure 105;

O’Donoghue and O’Donoghue 1923, p 23; 1925, p 100; 1926, p 48.

Dendrobeania lichenoides: Osburn 1950, p 167 , Plate 25, Figure 6 ; McCain and Ross 1974, p 13; Dick and Ross 1986, p 89; 1988, p 51, Plate 4D; Soule et al. 1995, p 104, Plate 34A–C.

Description

Colony. Recumbent, tan-coloured lobes similar in appearance to some foliose lichens, loosely attached to substrate by radicles ( Figure 6F ) originating from basal distolateral corner of some zooids; unilaminar, but younger lobes of a colony can overlap older lobes; up to 5–10 cm across.

Zooids. Club-shaped in outline ( Figure 6E ), rounded distally, widest at orifice, tapering and truncate proximally, each overlapping next distal zooid, 0.60–0.90 mm long (average 50.716 mm, n 515, 3) by 0.23–0.35 mm wide (average 50.306 mm, n 515, 3). Walls weakly calcified, flexible; adjacent zooids loosely appressed to one another; margins sharp. Opesia occupies entire visible frontal surface; proximal gymnocyst covered by preceding zooid; cryptocyst lacking.

Spines ( Figure 6E ). A straight, erect or distally angled spine at each distolateral corner and a total of three to six more-or-less curved spines along the lateral margins, paired or unequally distributed, angled over the opesia, with no more than four per side.

Avicularia. Lacking.

Ovicell ( Figure 6E ). Hyperstomial, globose, smooth, imperforate; broader than long, 0.25– 0.33 mm wide (average 50.288 mm, n 515, 3) by 0.18–0.25 mm wide (average 50.202 mm, n 515, 3).

Ancestrula . Not observed.

Remarks

Aggregated colonies formed extensive mats on the undersides of some boulders at East Tongass Narrows.

Distribution

Known from San Francisco ( Robertson 1900, 1905) to Kodiak Island in the Western Gulf of Alaska ( Dick and Ross 1988), with a number of records in between; also recorded from several localities around the Commander Islands ( Grischenko 1997, 2004).

Infraorder ASCOPHORINA Levinsen, 1909 ‘‘Grade’’ ACANTHOSTEGA Levinsen, 1902 Superfamily CRIBRILINOIDEA Hincks, 1879 Family CRIBRILINIDAE Hincks, 1879 Genus Cribrilina Gray, 1848 Cribrilina annulata ( Fabricius, 1780)

( Figure 7A, B )

Cellepora annulata Fabricius 1780, p 436 .

Cribrilina annulata: Robertson 1900, p 234 ; O’Donoghue and O’Donoghue 1923, p 30; 1926, p 50; Osburn 1950, p 177, Plate 28, Figure 7 ; Kluge 1975, p 470, Figure 247; Hayward and Ryland 1998, p 314, Figure 110; Dick and Ross 1986, p 89; 1988, p 51, Plate 4C.

Description

Colony. Encrusting, forming circular or irregular sheets on hard substrates; pink to reddish in colour; largest observed 1.5 cm across, but generally, 0.7 cm; unilaminar, with scattered frontally budded dwarf ovicellate zooids.

Zooids. Autozooids rounded-hexagonal to oval ( Figure 7A, B ); separated by a groove; 0.35–0.69 mm long (average 50.524 mm, n 515, 3) by 0.30–0.53 mm wide (average50.356, n 515, 3); basal wall uncalcified except for marginal shelf.

Frontal wall. Convex, inflated; frontal shield with 12–17 smooth, rounded, tapering costae connected along their lengths, tips meeting at midline, where there is sometimes a slight keel; each costa with a minute pseudopore at the tip; distalmost pair of costae usually thicker than the rest, forming proximal rim of orifice, the fused tips often raised as a suboral mucro; between adjacent costae are a marginal pore and three to six smaller intercostal pores, their diameter less then the intercostal struts between them; 6–12 intercostal pores in a transverse series across zooid at widest point.

Orifice. Orifice of non-ovicellate zooids 0.09–0.12 mm long (average 50.11 mm, n 515, 3) by 0.14–0.18 mm wide (average 50.160 mm, n 515, 3), rounded distally, broadly concave proximally.

Spines. Usually four (sometimes three) short, stout, erect spines around distal margin of orifice, the middle pair often shorter than lateral pair and sometimes fused as a single broad spine ( Figure 7B ).

Ovicells. Ovicellate zooids occur in primary layer in some colonies ( Figure 7B ); smaller than non-ovicellate autozooids, 0.31–0.63 mm long including ovicell (average 50.527 mm, n 515, 2) by 0.21–0.38 mm wide (average 50.301 mm, n 515, 2), with fewer costae (11– 14). Most colonies also have small, frontally budded, dwarf ovicellate zooids ( Figure 7A, B ) orientated in any direction, 0.20–0.35 mm long including ovicell (average 50.299 mm, n 518, 4) by 0.18–0.25 mm wide (average 50.228 mm, n 518, 4); frontal shield reduced, with three to four short frontal costae in addition to the pair of heavy costae comprising proximal lip of orifice; orifice proximo-distally compressed. Ovicells of primary and dwarf zooids similar, the proximal margin formed by a pair of heavy costae fused at the midline, often ending in a blunt point; distal to thickened costae is a cap-like chamber perforated on top with one to four pores (typically two) that sometimes merge with one another. Pseudopores at tips of proximal ovicellar costae appear as additional small perforations.

Avicularia. Lacking.

Ancestrula . Similar in form to autozooid, though smaller, 0.30–0.38 mm long (average 50.349 mm, n 511) by 0.20–0.30 mm wide (average 50.247 mm, n 511), with four (rarely five) orificial spines. Ancestrula typically first buds a distal zooid, then a pair of distolateral zooids, after which budding continues simultaneously from daughter zooids and proximal half of ancestrula; ultimate compliment of periancestrular zooids is six (one distal, two distolateral, two proximolateral, one proximal, with the proximal zooid abutting the ancestrula, but produced by and connecting to the two proximolateral zooids). Variations occasionally occur in initial budding order.

Remarks

Ketchikan specimens show some differences from material described from other parts of the range of this broadly distributed nominal species. For example, there is a tendency for the middle pair of orificial spines to fuse into a single broad spine ( Figure 7B ), whereas this has not been reported for material from Britain ( Hayward and Ryland 1998), high latitudes ( Kluge 1975), or Kodiak ( Dick and Ross 1988). In Ketchikan specimens, as in material treated by Kluge (1975) and Dick and Ross (1988), a pair of heavy costal spines forms the thick proximal margin of the ovicell, whereas in British material, the homologous pair of spines curve across the frontal surface of the ovicell, forming a transverse rib separate from the thin proximal margin. Finally, the ancestrular budding pattern seen at Ketchikan seems to differ from that of some other populations. For example, Nikulina (2002) illustrated and noted five periancestrular zooids for specimens from the White Sea; the proximal zooid seen in our material is apparently lacking. These kinds of variation perhaps indicate that across its range, nominal C. annulata may comprise several cryptic biological species; however, there is no basis at present for considering the Ketchikan material as distinct from C. annulata (Fabricius) .

We observed colonies of two different reproductive modes at Ketchikan. In the more common mode, the primary layer lacks ovicellate zooids; dwarf zooids are produced early in colony astogeny and tend to be clustered in the centre of small colonies. In the alternative mode, ovicellate zooids occur in the primary layer; dwarf zooids are not produced early on, and if they occur at all, are in more peripheral positions. We were unable to distinguish any other morphological differences between colonies of the two modes.

Distribution

This is considered a circumpolar, arctic-boreal species. Along the Pacific coast of North America, it has previously been reported from Point Barrow, Kodiak, Cordova, and Yakutat, Alaska ( Robertson 1900; Osburn 1950; Dick and Ross 1988), as well as British Columbia ( O’Donoghue and O’Donoghue 1923, 1926). On the Asian side, it has been reported from as far south as southern Hokkaido Island in Japan ( Mawatari and Mawatari 1981), and the northwest coast of the Sea of Japan ( Kubanin 1997).

Figures

Figure 6. (A, B) Bugula pacifica Robertson: (A) general colony view; (B) autozooids and lateral avicularia. (C, D) Bugula pugeti Robertson: (C) general colony view; (D) autozooids and lateral avicularia; note smaller avicularium near branch point (near top, right of centre). (E, F) Dendrobeania lichenoides Robertson: (E) autozooids and one ovicellate zooid; (F) abfrontal surface of portion of colony, showing attachment radicles. All specimens unbleached. Scale bars: 2 mm (A, C); 400 Mm (B); 1 mm (D, F); 500 Mm (E).

Figure 7. (A, B) Cribrilina annulata (Fabricius): (A) autozooids and frontally budded dwarf ovicellate zooids; bleached; (B) autozooids (lower right), ovicellate zooids in primary layer (lower centre and left), and frontally budded dwarf ovicellate zooids (top); bleached. (C–F) Cribrilina corbicula (O’Donoghue and O’Donoghue): (C) astogenetically young autozooids; unbleached; (D) ovicellate zooids in primary layer and frontally budded dwarf ovicellate zooids; bleached; (E) ovicellate zooids in primary layer and newly forming dwarf ovicellate zooids with membranous front only (upper left of centre) or with incomplete costae (lower right and centre); note compressed, subspatulate suboral costae; unbleached; (F) ancestrula and surrounding zooids; unbleached. Scale bars: 500 Mm (A–E); 1 mm (F).

Figure 8. (A–D) Puellina caesia n. sp.: (A) group of autozooids; bleached; (B) group of ovicellate zooids; bleached; (C) colony margin showing several stages of ovicell formation; bleached; (D) enlargement showing setiform papillae proximolateral to orifice; unbleached. Scale bars: 400 Mm (A); 500 Mm (B, C); 200 Mm (D).