Hippoporina titan, Almeida & Larré & Vieira, 2021

Hippoporina titan n. sp.

( Fig. 8A–D View FIGURE 8 )

urn:lsid:zoobank.org:act:E963A841-6D54-4B32-A730-E4587C7A69CF

Hippoporina sp. : Almeida et al. 2015a: p. 4; Souza & Almeida 2017: p. 266.

Material examined. Holotype: UFBA 1974.1 , 12º50’ S, 38º11’ W, Camaçari, Costa dos Coqueiros, Bahia, Brazil, 23 m, coll. by LAMEB-UFBA, 2007 GoogleMaps . Paratypes: UFBA 2237.5 , 12º47’ S, 38º06’ W, Camaçari, Costa dos Coqueiros, Bahia, Brazil, 26 m, coll. by LAMEB-UFBA, 2006 GoogleMaps ; UFBA 2997.5 , 12º50’ S, 38º11’ W, Camaçari, Costa dos Coqueiros, Bahia, Brazil, 23 m, coll. by LAMEB-UFBA, 2009 GoogleMaps ; UFPE 886 , 4 º49’– 5º10’ S, 36º10’– 36º50’ W, Bacia Potiguar, Rio Grande do Norte, Brazil, coll. by Petrobras, 2009–2010 GoogleMaps . Additional specimens: UFBA 99.3 , 12º50’ S, 38º11’ W, Camaçari, Costa dos Coqueiros, Bahia, Brazil, 23 m, coll. by LAMEB-UFBA, 2008 GoogleMaps ; UFBA 213.1 , 12º51’ S, 38º12’ W, Camaçari, Costa dos Coqueiros, Bahia, Brazil, 23 m, coll. by LAMEB-UFBA, 2004 GoogleMaps ; UFBA 1239.1 , Atol das Rocas, Rio Grande do Norte, Brazil, coll. by Ruy Kikuchi .

Diagnosis. Hippoporina with large subquadrangular to polygonal autozooids, zooids longer than 1 mm (up to 1.5 mm long), with nodular frontal wall with minute pseudopores excepted near to the proximal orificial area, and hyperstomial ovicell with ectooecium with 20 or more irregular pseudopores.

Type locality. Camaçari , Bahia, Brazil .

Etymology. Greek titan , one of the giant pre-Olympian gods in Greek mythology, alluding to the characteristic gigantic zooids found in this species.

Description. Colony encrusting ( Fig. 8A View FIGURE 8 ).

Autozooids subquadrangular to polygonal, distinctly large, longer than wide (1.048–1.262– 1.569 mm long, n = 15, SD = 0.164 mm; 0.802–0.962– 1.301 mm wide, n = 15, SD = 0.132 mm), with arched distal edge, separated by distinct sutures along slightly raised lateral walls ( Fig. 8B View FIGURE 8 ). Frontal shield weakly convex, with regularly spaced nodules and minute pseudopores, but often imperforate right below proximal margin of orifice; large marginal pore placed at each proximal corner ( Fig. 8B, C View FIGURE 8 ). Primary orifice subcircular (0.340–0.369– 0.432 mm long, n = 15, SD = 0.024 mm; 0.315–0.352– 0.383 mm wide, n = 15, SD = 0.022 mm), with a semicircular distal margin, a pair of almost mediolateral, small, triangular condyles and a wide, shallowly concave, proximal margin ( Fig. 8B View FIGURE 8 ). Peristome forming a slightly raised wall around primary orifice, without suboral umbo, obscuring primary orifice and sometimes forming a straight proximal margin, especially in ovicelled zooids.

Avicularia not observed.

Ovicell hyperstomial, subglobular with flattened frontal area (0.567–0.627– 0.689 mm long, n = 5, SD = 0.060 mm; 0.825–0.861– 0.906 mm wide, n = 5, SD = 0.041 mm); endooecium calcified ( Fig. 8C View FIGURE 8 ); ectooecium with 20 or more irregular pseudopores that can be merged ( Fig. 8C, D View FIGURE 8 ); ovicelled zooids often with straight and raised peristome, obscuring proximal orifice margin.

Remarks. Like other species of the genus, Hippoporina titan n. sp. has autozooids with frontal pores except in the suboral region, primary orifice with paired lateral condyles leaving a shallow poster and pseudoporous ectooecium ( Cook 1985). Most of the 23 living Hippoporina species have autozooids that are less than or up to one mm in length, with large frontal pseudopores, proximolateral condyles and a suboral umbo (e.g., Cook 1964; Osburn 1952; Winston 2005; Winston & Woollacott 2009). Hippoporina titan n. sp. is distinguished from these species by its much larger zooid size, minute frontal pseudopores, mediolateral condyles and peristome with distinct lateral margins.

At least three species of Hippoporina have been reported from Brazil — Hippoporina indica Madhavan Pillai, 1978 , Hippoporina pertusa ( Esper, 1796) and Hippoporina sertata ( Canu & Bassler, 1930) ( Vieira et al. 2021) . The three species have moderately sized autozooids (less than 1 mm long), large frontal pseudopores, proximal condyles and avicularia ( Canu & Bassler 1930; Cook 1964; McCann et al. 2007).

Distribution. Western Atlantic: Brazil (Bahia and Rio Grande do Norte). Hippoporina titan n. sp. is commonly associated with rhodoliths and calcareous nodules; 23‒ 26 m.