Microporella proxima, Ramalho & Muricy & Taylor, 2011
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publication ID |
https://doi.org/ 10.1080/00222933.2010.535917 |
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persistent identifier |
https://treatment.plazi.org/id/03C387A4-EC50-3771-F484-FDF5FD05FA3B |
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treatment provided by |
Felipe |
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scientific name |
Microporella proxima |
| status |
sp. nov. |
Microporella proxima sp. nov.
( Figure 6 View Figure 6 )
Examined material
Holotype: MNRJ-180, Macaé, Rio de Janeiro State, Brazil, collected by J.E.A. Gonçalves, 14 December 2002, on Sargassum from the hull of the Valentin Shashin, depth 3 m.
Etymology
The name proxima refers to the position of avicularium, near to the zooidal margin and more proximal than most other species of Microporella .
Diagnosis
Microporella with encrusting colony; autozooids small, averaging 416 µm long by 322 µm wide; frontal wall pustolose, evenly perforated by pseudopores and with narrow, inconspicuous areolar pores around the edges; orifice D-shaped, slightly flattened, the proximal edge beaded, four oral spines, one pair distally and the other pair mediolaterally; ascopore reniform with short, tooth-like spines, situated on a raised area of frontal shield; avicularium single, located near the margin, about mid-length on the autozooid, distant from ascopore, oriented laterally to distolaterally, mandible elongated, setose, irregular.
Description
Colony encrusting, unilamellar ( Figure 6A View Figure 6 ), up to 1 cm in diameter. Early astogeny unknown.
Autozooids disposed in quincunx, rounded rhombic in frontal outline, separated by deep grooves, small, higher than wide (416 µm long, range 392–441 µm, by 322 µm wide, range 294–343 µm). Frontal wall convex with granulations and rounded pseudopores scattered across entire surface except for area between ascopore and orifice ( Figure 6B View Figure 6 ); areolar pores inconspicuous, more elongate than pseudopores. Orifice D-shaped (70 µm long, range 64–79 µm, by 105 µm wide, range 93–107 µm), slightly flattened, proximal border straight, beaded; oral spines delicate ( Figure 6C View Figure 6 ), four in number, one pair distal and the other pair mediolateral, not close to the proximal corners of orifice; only two spines generally visible in ovicellate zooids. Ascopore reniform, located on a raised area of frontal shield, margin with minute teeth ( Figure 6D View Figure 6 ). Ovicell prominent, closed by zooidal operculum, almost round, slightly higher than wide; surface similar to an autozooidal frontal shield, porous and granular ( Figure 6D View Figure 6 ).
Avicularium single, located laterally roughly midway along autozooid, rarely close to the orifice, directed laterally or distolaterally; mandible elongate, (209 µm long, range 196–216 µm), pointed, thin and irregular (not straight), turned distolaterally ( Figure 6C,D View Figure 6 ).
Habitat
Colonies found on algae ( Sargassum ) growing on the hull of the Valentin Shashin.
Geographical distribution
Macaé. Colonies were collected from the hull of the drilling ship Valentin Shashin but as this has remained in this area for a least 5 years, it seems likely that the new species is established here and did not colonize when the ship was elsewhere.
Remarks
In the past, this species would probably have been determined as Microporella ciliata (Pallas, 1766) . However, many identifications of M. ciliata are now considered incorrect, having been made before the concept of the species was stabilized by Kuklinski and Taylor (2008) through the selection of a neotype, NHM 2008.02.06.1, from the Bay of Naples.
Comparing Microporella proxima sp. nov. with the similar M. ciliata , the following differences are evident: (1) M. ciliata has smaller pseudopores; (2) autozooids are larger in M. ciliata than in M. proxima , average lengths being 790 and 420 µm respectively; (3) the avicularium is located more proximally and further away from the ascopore in M. proxima ; and (4) the most proximal pair of oral spines is just above the proximolateral corners of the orifice in M. ciliata but more distally located in M. proxima .
Marcus (1937, 1955) described putative M. ciliata from São Paulo and Espírito Santo states but his material represents neither M. ciliata nor M. proxima and is in need of revision. Canu and Bassler’s (1928) material from Brazil identified as M. ciliata differs from M. proxima because it has a transverse avicularium located between the orifice and ascopore, and very large autozooids.
Another species very similar to Microporella proxima sp. nov. is M. monilifera Liu and Liu, 2003 , the two species having avicularia and ascopores of the same shape and similar-sized autozooids. However, the Chinese species has up to five oral spines, a smooth proximal border to the orifice, smaller pseudopores, and the avicularium is located nearer to the ascopore.
Winston (2005) described a new species of Microporella , M. protea , from the Atlantic with a distribution stretching south from Cape Hatteras to Florida, and possibly into the Caribbean. This species is similar to the new Brazilian species in its orifice shape, beaded proximal border, number and positions of oral spines. However, it differs in having wider zooids, in the shape and size of the avicularia, which are located more distally, and in the less elongate ascopore.
The species Microporella gibbosula Canu and Bassler, 1930 , originally described from the Galapagos Islands, is similar to M. proxima sp. nov. in both avicularium shape and position (located near the margin and the zooidal lateral angle) and the setose mandible. However, it differs in its larger autozooids (500–550 µm long and 450 µm wide), five distal spines, a small ascopore and smooth ovicells.
Approximately 100 species of Microporella have been recognized, the number increasing as more use is made of SEM ( Taylor and Mawatari 2005). Many established species remain to be characterized using SEM and some supposedly cosmopolitan species, notably M. ciliata , are undoubtedly complexes of more narrowly distributed species such as M. proxima sp. nov.
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