Microporella acicularis, Judith L Winston, 2016

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

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Microporella acicularis

sp. nov.

Microporella acicularis  sp. nov.

( Fig. 32View FIGURE 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. 32View FIGURE 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. 32View FIGURE 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. 32View FIGURE 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. 32View FIGURE 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

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

Mean 0.543     0.100   0.290       0.057
  0.043     0.008   0.019       0.007
  0.450     0.090   0.270       0.054
  0.612     0.108   0.324       0.072