Sertularella arbuscula ( Lamouroux, 1816 ) Sertularella patagonica ( d’ Orbigny, 1846 )

Gil, Marta & Ramil, Fran, 2021, Hydroids (Cnidaria, Hydrozoa) from the Vema and Valdivia seamounts (SE Atlantic), European Journal of Taxonomy 758, pp. 49-96 : 69-70

Sertularella arbuscula ( Lamouroux, 1816)

Table 9

Sertularia arbuscula Lamouroux, 1816: 191–192 , pl. 5 fig. 4.

Sertularella crassipes Allman, 1886: 133–134 , pl. 8 figs 4–5.

Sertularella arbuscula – Millard 1975: 281–282, fig. 91j–l.

Material examined

SOUTH ATLANTIC OCEAN • 2 colonies, up to 31 mm high, without gonothecae; Vema Seamount , stn PT4; 31°39′43″–31°38′10″ S, 8°22′37″–8°23′42″ E; 50–108 m depth; 31 Jan. 2015; SEAFO-2015 leg.; SEAFO-2015-40093 , SEAFO-2015-40123 • 2 colonies, up to 40 mm high growing on algae, without gonothecae; Vema Seamount , stn BT5; 31°37′16″–31°36′58″ S, 8°22′37″–8°23′06″ E; 71–94 m depth; 31 Jan. 2015; SEAFO-2015 leg.; SEAFO-2015-40527 , SEAFO-2015-40768 , LZM-UV slide R. 588 • 1 colony, 30 mm high, growing on bryozoan, with gonothecae; Valdivia Seamount , stn PT10; 25°36′54″–25°37′26″ S, 6°12′40″–6°11′31″ E; 476–707 m depth; 5 Feb. 2015; SEAFO-2015 leg.; SEAFO-2015-40414 .

Distribution

This species has been previously recorded from the Australasian Seas, Indian Ocean, South Africa and Vema Seamount, from the littoral zone to a depth of 219 m ( Millard 1966, 1975). Our records from Valdivia Bank, between 476 and 707 m, represent the deepest known localities for this species. Sertularella patagonica ( d’ Orbigny, 1846)

Fig. 4E ; Table 10

Sertularia patagonica d’ Orbigny, 1846: 25–26 , pl. 11 figs 3–5.

Sertularella striata – Millard 1975: 304–305, fig. 97e–f. — Gili et al. 1989: 104–105, fig. 29a. Sertularella patagonica – Galea et al. 2017: 294–295, fig. 15a–e.

Material examined

SOUTH ATLANTIC OCEAN • 11 colonies, up to 24 mm high (1 growing on antipatharian), all devoid of gonothecae; Vema Seamount , stn PT4; 31°39′43″–31°38′10″ S, 8°22′37″–8°23′42″ E; 50–108 m depth; 31 Jan. 2015; SEAFO-2015 leg.; SEAFO-2015-40003 , SEAFO-2015-40033 , SEAFO-2015-40077 , SEAFO-2015-40093 , SEAFO-2015-40107 , SEAFO-2015-40183 , SEAFO-2015-40213 , SEAFO-2015- 40474 , LZM-UV slide R. 586 • 4 colonies, without gonothecae (1 growing on algae and 1 on a bryozoan); Vema Seamount , stn BT5; 31°37′16″–31°36′58″ S, 8°22′37″–8°23′06″ E; 71–94 m depth; 31 Jan. 2015; SEAFO-2015 leg.; SEAFO-2015-40387, SEAFO-2015-40467, SEAFO-2015-40723, SEAFO-2015-40768 • 3 colonies, without gonothecae; Vema Seamount , stn Dive 4; 91–95 m depth; 1 Feb. 2015; SEAFO-2015 leg.; SEAFO-2015-40131 , SEAFO-2015-40917 , SEAFO-2015-40977 .

Remarks

Our material coincides in both morphology and measurements with those given for S. patagonica by Galea et al. (2017), who synonymized Sertularella striata Stechow, 1923 with S. patagonica after a literature review. It also fits well with the colonies described by Gili et al. (1989, as S. striata ) from the Namibian coast, but this record was considered as doubtful by Galea et al. (2017) due to the hydrothecal measurements being larger than those reported for S. patagonica in the literature. However, there are some contradictions between the measurements given by Gili et al. (1989) in the text and those that we have obtained from their figure 29a; indeed, the latter fall within the size range given for S. patagonica , and Namibian colonies prove identical with those collected at Vema Seamount. Consequently, we consider our Namibian material as conspecific with S. patagonica .

Distribution

In the Atlantic, Sertularella patagonica was recorded from the Argentinean coast ( Galea et al. 2017) and off Namibia ( Gili et al. 1989, as S. striata ), and from the east coast of South Africa, Mozambique (Millard 1975) and India ( Nagale & Apte 2014, as S. striata ) in the Indian Ocean. Its bathymetric distribution ranges from the intertidal ( Nagale & Apte 2014, as S. striata ) to 429 m ( Gili et al. 1989, as S. striata ).

Sertularella patagonica ( d’ Orbigny, 1846)

Fig. 4E ; Table 10

Sertularia patagonica d’ Orbigny, 1846: 25–26 , pl. 11 figs 3–5.

Sertularella striata – Millard 1975: 304–305, fig. 97e–f. — Gili et al. 1989: 104–105, fig. 29a. Sertularella patagonica – Galea et al. 2017: 294–295, fig. 15a–e.

Material examined

SOUTH ATLANTIC OCEAN • 11 colonies, up to 24 mm high (1 growing on antipatharian), all devoid of gonothecae; Vema Seamount , stn PT4; 31°39′43″–31°38′10″ S, 8°22′37″–8°23′42″ E; 50–108 m depth; 31 Jan. 2015; SEAFO-2015 leg.; SEAFO-2015-40003 , SEAFO-2015-40033 , SEAFO-2015-40077 , SEAFO-2015-40093 , SEAFO-2015-40107 , SEAFO-2015-40183 , SEAFO-2015-40213 , SEAFO-2015- 40474 , LZM-UV slide R. 586 • 4 colonies, without gonothecae (1 growing on algae and 1 on a bryozoan); Vema Seamount , stn BT5; 31°37′16″–31°36′58″ S, 8°22′37″–8°23′06″ E; 71–94 m depth; 31 Jan. 2015; SEAFO-2015 leg.; SEAFO-2015-40387, SEAFO-2015-40467, SEAFO-2015-40723, SEAFO-2015-40768 • 3 colonies, without gonothecae; Vema Seamount , stn Dive 4; 91–95 m depth; 1 Feb. 2015; SEAFO-2015 leg.; SEAFO-2015-40131 , SEAFO-2015-40917 , SEAFO-2015-40977 .

Remarks

Our material coincides in both morphology and measurements with those given for S. patagonica by Galea et al. (2017), who synonymized Sertularella striata Stechow, 1923 with S. patagonica after a literature review. It also fits well with the colonies described by Gili et al. (1989, as S. striata ) from the Namibian coast, but this record was considered as doubtful by Galea et al. (2017) due to the hydrothecal measurements being larger than those reported for S. patagonica in the literature. However, there are some contradictions between the measurements given by Gili et al. (1989) in the text and those that we have obtained from their figure 29a; indeed, the latter fall within the size range given for S. patagonica , and Namibian colonies prove identical with those collected at Vema Seamount. Consequently, we consider our Namibian material as conspecific with S. patagonica .

Distribution

In the Atlantic, Sertularella patagonica was recorded from the Argentinean coast ( Galea et al. 2017) and off Namibia ( Gili et al. 1989, as S. striata ), and from the east coast of South Africa, Mozambique (Millard 1975) and India ( Nagale & Apte 2014, as S. striata ) in the Indian Ocean. Its bathymetric distribution ranges from the intertidal ( Nagale & Apte 2014, as S. striata ) to 429 m ( Gili et al. 1989, as S. striata ).

Figures

Fig. 4. A. Clytia gigantea (Hincks, 1866), portion of colony with three hydrothecae. B. Amphisbetia minima (Thompson, 1879), portion of hydrocladia with hydrothecae and basal gonotheca.C. Sertularella areyi Nutting, 1904, part of hydrocladia with hydrothecae. D. Sertularella polyzonias (Linnaeus, 1758), part of hydrocladia with hydrotheca and one gonotheca. E. Sertularella patagonica (d’ Orbigny, 1846), part of hydrocladia with hydrothecae.

Tables

Table 9. Measurements of Sertularella arbuscula (Lamouroux, 1816), in µm.

	SEAFO-2015
	Stn BT5
Internode, length	600–790
diameter	340–410
Hydrothecae, length adcauline wall, adnate part	390–450
length adcauline wall, free part	260–340
length abcauline wall	450–540
diameter at rim	200–290