Brooksia rostrata Traustedt, 1893

Ishak, Nurul Huda Binti Ahmad, ‘ Aliah, Nur, Adam, Binti & Kassim, Zaleha, 2018, A taxonomic revision of the genus Thalia Blumenbach, 1798; Weelia Yount, 1954; Brooksia Metcalf, 1918 (Salpida: Salpidae) from East Coast of Peninsular Malaysia, Zootaxa 4422 (4), pp. 451-477 : 467-468

4. Brooksia rostrata Traustedt, 1893

Salpa rostrata Traustedt, 1893 , pp. 8, pl. I, figs. 1 – 4 (cited in Thompson 1948 and Sewell 1926; Apstein, 1894, pp. 16, 36, pl. ii, figs. 9 , 17 – 19 (cited in Sewell 1926)

Brooksia rostrata Metcalf, 1918 , pp. 50 (cited in Sewell 1926); Fraser, 1947; Thompson, 1948: 120, pl. 43, pl. 45; Yount, 1954; van Soest, 1975; Chihara & Murano, 1997: 1381, pl. 7; Godeaux: 1998, pp. 287, fig. 17.16c; Kott, 2005; Hereu & Suárez- Morales, 2012; Garic & Batistic, 2016; Purushothaman et al. 2017; Franco et al. 2017

Specimens examined. In my study, this species was the present at 5 sampling sites. C2: 15 solitary zooids, 31 aggregate zooids, 5°25'33.93"N, 103°17'32.72"E, Jun 2016; C3: 16 solitary zooids, 13 aggregate zooids, 5°28'54.80"N, 103°22'55.42"E, Jun 2016; D1: 1 aggregate zooid, 5°14'5.31"N, 103°14'40.12"E, July 2016; D2: 4 aggregate zooid, 5°14'5.20"N, 103°16'36.04"E, July 2016; D3; 3 aggregate zooids, 5°15'50.06"N, 103°17'44.13"E, July 2016. Malaysia: East Cost of Peninsular Malaysia . UMTTn 0 0 0 7.

Description. Solitary ( Fig. 8a , Top & Middle; 8b): Body length reach 4.3 mm without anterior projection, and reaching 6 mm including the anterior projection. Body is elongatedly cylindrical; squaring posteriorly while strongly developing a projection anteriorly, below the lower lip, bearing four longitudinal muscles; which are extensions of the dorsal sphincters, and two ventral longitudinal muscles. The projection may be as long as the body, although in most specimen it is shorter. The test is lost in this specimen. There are 7 body muscles observed in the specimens. The muscles are arranged in two dorsal group (MI–MIII and MIV – MVII), where MI is joined by the intermediate muscle and MIII and MIV are converging laterally. The body muscles are ventrally interrupted by two longitudinal muscles which run from MVII to the anterior tip of the anterior projection. The dorsal tubercle located close in front of the ganglion, very slightly curved. The ganglion carries the broad horseshoe eye and located in front of MI. The alimentary canal is coiled into a loose nucleus, located immediately behind MVII. The endostyle is slightly curved, reaches back to at least near MIV. Ihle states that it reaches between MIV and MV, but according to Traustedt it only reaches to MIII. This specimen resembles more to Ihle than to Traustedt. The gill is slender. Stolon runs forward in a more or less straight course on the mid ventral line.

Aggregate ( Fig. 8a , Bottom; 8b): Body is oval shaped. The test is lost in this specimen. Due to the poor state of preserved specimens, it is impossible to study the body muscles. Van Soest (p. 116) stated the number of fibers could vary from 14–26 fibers. This specimen agree to the range of fibers count. The alimentary canal is coiled into a rather tight nucleus, which lies at the posterior most part of the body. The endostyle is short, bent to a hook in front, near its point of origination neighboring behind the oral siphon. Ovary and embryo is situated between MIII and M IV on the right side. The gills are slender.

Remarks. Both solitary and aggregate zooids of this species were found during the sampling of this study. The aggregate seems to be unfit for critical taxonomy study due to poor preservation that caused specimen shrinkage. The solitary and aggregate zooids conforming to Thompson's (1948) figures. Fedele (1926) figured an aggregate specimen with very long attachment organs; no such specimens were encountered in the present material.

Distribution. Distributional data on Brooksia rostrata reported that it mainly occurred in temperate waters (van Soest 1975). Records from the Atlantic Ocean includes the occurrence on southeast of Bermuda (Madin et al. 1996) and Caribbean Sea and the Gulf of Mexico (Hereu & Suárez-Morales 2012). It has also been found in the Arabian Sea (including the Laccadive Sea), the Bay of Bengal and the Andaman Sea ( Sewell 1926), Gulf of Naples ( Fedele 1926), Red Sea and Gulf of Suez ( Godeaux 1974), Gulf of Aden and Hanish Hill ( Godeaux 1987) and Adriatic Sea ( Sigl 1912; Batistić et al. 2014). Records found from the Pacific Ocean includes (Yount 1954; 1958), Australian Seas ( Thompson 1948), Province of Izu ( Tokioka 1937; 1960), European waters (Costello et al. 2001), Kaoping Trench, southwestern waters of Taiwan ( Tew & Lo 2005), Taiwan waters ( Liao et al. 2013 & Franco et al. 2017) and Indo-West Pacific (van der Land 2008). The compilation of previous literature and present data distribution of Brooksia rostrata is shown in Figure 9 .

Figures

FIGURE 8a. Brooksia rostrata (Traustedt, 1893). Top, Solitary zooid; Middle, posterior part; Bottom, Aggregate. Br, branchial septum; Dt., dorsal tubercle; End, endostyle; G, ganglion, i.m., intermediate muscle; N, nucleus; o.m., oral musculature.

FIGURE 9. Distribution of Brooksia rostrata (Traustedt, 1893). Red dots: specimen examined by the author; black dots: records based on compilation of previous literature data.