Microporella acicularis, Judith L Winston, 2016

Judith L Winston, 2016, Bryozoa of Floridan Oculina reefs, Zootaxa 4071 (1), pp. 1-81 : 59

Microporella acicularis sp. nov.

( Fig. 32 ; Table 31 )

Material examined. Holotyp e: VMNH no. 70646. Paratype: USNM no. 1283256.

Additional material: VMNH no. 70647.

Etymology. Latin, acicularis , needle-like, alluding to the long needle-like avicularian mandibles.

Diagnosis. Microporella species with 4–5 orificial spines, a semicircular ascopore just proximal to orifice, and paired avicularia with needle-like mandibles that can be as long as zooids when intact and oriented distally to slightly distolaterally.

Description. Colony encrusting ( Fig. 32 A). Zooids oval to rhombic, frontal shield convex, with surface texture of closely spaced hemispherical bumps, with small pores between them. Primary orifice subcircular, but with straight or slightly concave proximal margin, and two low condyles on either side ( Fig. 32 E, F). Distal oral spines typically 5, hollow. Peristome low, textured like frontal shield. Ascopore toothed, semicircular, located medially close to proximal margin of orifice. Avicularia triangular, mostly paired, with complete crossbars and channeled rostral tips ( Fig. 32 C), positioned subjacent to orfice on both sides at level of ascopore, oriented almost distally at angle c. 70–80°. Mandibles long, thin, acute ( Fig. 32 C, D), as long as autozooids when unbroken. Ooecium globular, textured like frontal shield, terminating proximally near proximal edge of orifice, not forming bridge across it.

Remarks. Microporella ampla Canu & Bassler, 1928 a is similar in having a convex pebbly frontal shield, an ascopore close to the proximal margin of the orifice, paired near-distal avicularia and five orificial spines. However, M. ampla zooids are considerably larger, being 0.70–0.74 mm long by 0.50 mm wide according to Canu & Bassler’s description, have a round ascopore, and any slight deviation of the avicularia direction is toward the orifice, whereas in M. acicularis the tilt is slightly lateral.

Distribution. Atlantic Florida shelf, Oculina reefs

Figures

FIGURE 32. Microporella acicularis sp. nov.: A, colony encrusting the inner face of a dead barnacle plate, small but sexually mature; B, uncleaned autozooids, showing acicular avicularian mandibles; C, zooid with ooecium; D, closed mandibles of avicularia; E, orifice and distal end of zooid; F, uncleaned zooids showing operculum and portions of open and closed mandibles. Scale bars: A, 1 mm; B, 0.5 mm; C, 0.1 mm; D, F, 0.2 mm. E. 0.02 mm.

Tables

TABLE 31. Measurements in mm of Microporella acicularis sp. nov.

	Lz	Wz	Lo	Wo	Lov	Wov	Lavm	Wavm	Lav	Wav
N	12	12	12	12	8	9	6	6	6	6
Mean	0.543	0.387	0.080	0.100	0.221	0.290	0.303	0.056	0.089	0.057
SD	0.043	0.058	0.009	0.008	0.023	0.019	0.048	0.009	0.004	0.007
Min	0.450	0.324	0.072	0.090	0.198	0.270	0.252	0.045	0.081	0.054
Max	0.612	0.540	0.090	0.108	0.270	0.324	0.360	0.072	0.090	0.072