Aulocyathus juvenescens von Marenzeller, 1904a

Filander, Zoleka N., Kitahara, Marcelo V., Cairns, Stephen D., Sink, Kerry J. & Lombard, Amanda T., 2021, Azooxanthellate Scleractinia (Cnidaria, Anthozoa) from South Africa, ZooKeys 1066, pp. 1-198 : 1

Aulocyathus juvenescens von Marenzeller, 1904a

Fig. 1G, H

Aulocyathus juvenescens von Marenzeller, 1904a: 301-302, pl. 18, fig. 17. - Zibrowius 1980: 107. - Cairns and Keller 1993: 247. -Cairns 1994: pl. 26, figs H, I. - Cairns and Zibrowius 1997: 130. - Cairns 1999a: 104, fig. 15H. - Kitahara and Cairns 2021: 409-411, figs 221, 222G-I.

Type locality.

Off Pemba and Zanzibar Island, Tanzania (SS ' Valdivia ' stn. 243 and 245: 6°39'1"S, 39°30'8"E, 5°27'9"S, 39°18'8"E, respectively); 400-463 m (von Marenzeller 1904a).

Type material.

Syntypes are deposited at the ZMB ( Cairns and Keller 1993).

Material examined.

None.

Imagery data.

'Galathea Expedition’ stn. 196 (2 specimens): Eastern margin, 33 km off Durban/31 km off Beachwood Mangroves, 29°55'00.00"S, 31°19'59.99"E; 425-430 m. 'Mortensen-Java Expedition’ stn. 25 (1 specimen): Eastern margin, off Durban, 424 m.

Description.

Corallum solitary, ceratoid, and usually attached to a fragment of the parent corallum. Calice circular, with finely serrated calicular margin. Largest imaged specimen (Galathea Expedition stn. 196) 6.5 × 6.5 mm in CD, and ≤ 11.0 mm in H. Costae restricted to calicular margin, with low intercostal striae. Theca smooth and porcelaneous. Corallum white, with longitudinal light brown pigmentation.

Septa hexamerally arranged in four cycles, the last cycle being incomplete, according to the formula: S1> S2> S3> S4 (30 septa). S1 most exsert septal cycle. S2 slightly less exsert than S1, being 3/4 the width of S1. S3-4 progressively less exsert. S3 dimorphic in size: those in half systems lacking S4 only ½ the width of S2, and those flanked by a pair of S4 attain the same width as S2. If present, S4 ½ the size of S3. All septa with vertical and slightly sinuous axial margin, S3-4 bearing dentate axial margins deeper on fossa. All septal faces with fine granulations. Fossa deep containing a rudimentary columella.

Distribution.

Regional: Eastern margin of South Africa, off Durban; 424-430 m. Elsewhere: Vanuatu; Philippines ( Cairns 1999a); New Caledonia ( Kitahara and Cairns 2021); Tanzania (von Marenzeller 1904a; Cairns and Keller 1993); 182-790 m.

Remarks.

The imagery records of Aulocyathus juvenescens represent a distributional range extension for this species further south of Tanzania and are also new records for South Africa. Although these specimens have no more than 30 septa, their morphology is consistent with the taxonomic diagnosis of the species detailed by von Marenzeller (1904a). Amongst the four recent species of the genus, A. juvenescens has the smallest CD, least number of septa, and a porcelaneous theca ( Cairns 1999a).

Figures

Figure 1. A, B Anomocora fecunda (SAMC _ A 073042, off Shaka's Rock, 200 m) A calicular view B lateral view C, F Anomocora marchadi C, D (SAMC _ A 090093, off Durban, 49 m) C calicular view D lateral view E, F (SAM _ H 3100, off Shaka's Rock, 66 m) E calicular view F lateral view G, H Aulocyathus juvenescens (Mortensen 25, off Durban, 424 m) G calicular view H lateral view I, J Aulocyathus sp. cf. Aulocyathus matricidus (DIa 1, locality data unknown) I calicular view J lateral view K, L Caryophyllia (Acanthocyathus) grayi (USNM 91541, off Kosi Bay, 98 m) K calicular view L lateral view M, N Caryophyllia (Caryophyllia) diomedeae (MN _ SM 129, off Margate, 850 m) M calicular view N lateral view N, O Caryophyllia (Caryophyllia) ephyala (SAMC _ A 072974, off Paternoster, 440 m) O Calicular view P Lateral view. Scale bars: 10 mm.