Hippopleurifera barbosae, Ramalho, Laís V., Távora, Vladimir A., Tilbrook, Kevin J. & Zágoršek, Kamil, 2015

Ramalho, Laís V., Távora, Vladimir A., Tilbrook, Kevin J. & Zágoršek, Kamil, 2015, New species of Hippopleurifera (Bryozoa, Cheilostomata) from the Miocene Pirabas Formation, Pará state, Brazil, Zootaxa 3999 (1), pp. 125-134 : 128-130

publication ID

https://doi.org/ 10.11646/zootaxa.3999.1.8

publication LSID

lsid:zoobank.org:pub:2E2A85AC-25DF-4619-AD84-FF1D6EE6844E

DOI

https://doi.org/10.5281/zenodo.6122728

persistent identifier

https://treatment.plazi.org/id/292BD20F-E161-FFDB-DBA0-3EF1FB82FC93

treatment provided by

Plazi

scientific name

Hippopleurifera barbosae
status

sp. nov.

Hippopleurifera barbosae View in CoL sp. nov.

( Figs 2 View FIGURE 2 A–F)

Material examined. Holotype: MG–6301–I–a, Atalaia Beach, Salinópolis, Pará state, Brazil. Paratypes: MG– 6301–I–b to n, same locality as holotype.

Diagnosis. Colony encrusting. Autozooids rectangular to polygonal; frontal shield with 1–4 rows of areolar pores. Orifice with 4 distal spines and a median lyrulate convexity, sometimes denticulate. A single suboral avicularium and a pair (usually) of lateral and asymmetrical avicularia. Oecium hyperstomial, with perforated entooecium and smooth bifenestrate ectooecium bearing two small avicularia.

Description. Colony encrusting. Autozooids rectangular to polygonal, longer than wide (633–1121 [800] µm x 468–633 [526] µm). Frontal shield with 1–4 rows of areolar pores, leaving the central region imperforate ( Fig. 2 View FIGURE 2 A– C). Interior of frontal shield not well preserved, but 3–4 rows of areolar pores can be seen with small, smooth central area proximal to orifice ( Fig. 2 View FIGURE 2 F).

Primary orifice slightly longer than wide (235–286 [255] µm x 235–262 [244] µm); anter evenly rounded, bordered by 4 spine bases, the distalmost pair closer to each other than the more proximal pair ( Fig. 2 View FIGURE 2 C) [Laís, this is not easy to discern in 2C, but is seen in 2D.]; maternal zooids have only 2 spines visible ( Fig. 2 View FIGURE 2 D); poster concave, with prominent median lyrulate convexity on proximal rim, sometimes weakly denticulate ( Fig. 2 View FIGURE 2 B–D); a pair of short rounded-triangular condyles adjacent to proximalmost spines ( Fig. 2 View FIGURE 2 C, D).

Single small suboral avicularium (100–176 [128] µm long), always on a raised cystid ( Fig. 2 View FIGURE 2 A–D); rostrum triangular, directed distofrontally ( Fig. 2 View FIGURE 2 C, D); crossbar complete; rostral tip often ending on the lyrulate convexity ( Fig. 2 View FIGURE 2 B–D). Lateral avicularia often paired and asymmetrical in position, or simple, directed distally, parallel to or angled away from lateral border of orifice ( Fig. 2 View FIGURE 2 A–D); variable in size (84–262 µm long) as well as shape ( Fig. 2 View FIGURE 2 B, C); rostrum elongate-rounded, or sometimes spatulate; crossbar complete ( Fig. 2 View FIGURE 2 A–C).

Ooecium hyperstomial, wider than long (233–407 [332] µm x 367–471 [425] µm), entooecium perforated by small pores, ectooecium smooth, thick, surrounding external border and frontal surface, forming a central keel, resulting in the ooecium appearing bifenestrate ( Fig. 2 View FIGURE 2 E). Two small adventitious avicularia (96–144 µm long) often developed proximofrontally on ectooecium, asymmetrical, directed proximomedially, one situated on each side of the central keel ( Fig. 2 View FIGURE 2 B, D–E); rostrum rounded ( Fig. 2 View FIGURE 2 D, E), crossbar complete.

Etymology. Honorific for Dra. Maria Marta Barbosa who first studied the bryozoans from the Pirabas Formation.

Remarks. Some 25 species of Hippopleurifera have been described from around the world ( Bock 2012; Gordon 2014) (although the genus still needs to be reviewed; see comments above) but no Hippopleurifera species have yet been recorded from Brazil (fossil or Recent species). Most of the known species of Hippopleurifera are fossil, and most of these have six oral spines (although a few species may have up to seven), with lateral avicularia located near the proximal border of the orifice directed distally, but an umbo or suboral avicularium is not common. However, H. semicristata ( Reuss, 1847) has lateral avicularia similar in shape to those of H. barbosae sp. nov. but they are more proximally positioned and the number of oral spines is higher (five to seven). H. sedgwicki ( Milne Edwards, 1836) also resembles H. barbosae but this species has a significantly reduced, smooth area suborally on the frontal shield, only three to five oral spines, small oval, lateral avicularia and a bifenestrate ooecium. Finally, H. ampla ( Canu & Bassler, 1920) is the most similar to H. barbosae , mainly because of its possession of a suboral avicularium and bifenestrate oecium. However, the species are readily distinguished as H. ampla has a small elliptical, suboral avicularium, narrower zooids (220 µm), a smaller primary orifice (180 µm long x 200 µm wide) with a narrow cylindrical lyrula, only one or two rows of areolar pores and only a single lateral avicularium with a longer, more-spatulate rostrum. Canu & Bassler (1920) did not describe the ooecial surface of H. ampla , but neverthless illustrated an ooecium with what appears to be a pair of avicularia upon it ( Canu & Bassler 1920, fig. 15). Hippopleurifera barbosae sp. nov. is known only from the Pirabas Formation.

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