Weelia cylindrica Cuvier, 1804

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 : 459-465

3. Weelia cylindrica Cuvier, 1804

Salpa cylindrica Cuvier, 1804 (cited from van Soest 1973); ( Ritter & Byxbee 1905); (Survey 1918); ( Tokioka 1937); Thompson 1948; Godeaux 1998

Iasis cylindrica Savigny, 1816 (cited by Kott 2005); Franco et al. 2017; Purushothaman et al. 2017

Salpa coerulescens Chamisso 1819 (cited by Kott 2005)

Weelia cylindrica ; (Yount 1954); Van Soest 1975, 1998; Al-Yamani et al. 2011; Hereu & Suárez-Morales 2012

Specimens examined. 1 solitary zooids, 17 aggregate zooids, 5°25'33.93"N, 103°17'32.72"E, Jun 2016. Malaysia : East Cost of Peninsular Malaysia . UMTTn 0 0 0 6.

Description. Solitary ( Fig. 6a , Top; 6b): Body length reaches 20.7 mm. Body is elongated and cylindrical; rounded anteriorly, and squarely cut off posteriorly. The test is thin, soft and smooth with no projection or echination. There are 9 body muscles that extend rather far ventrally and are usually separated. The first four body muscles; MI – MIV are seen closely approaching in the mid-dorsal line. The muscle fibers for MI–MIX is a total of 181. There are 3 sphincters present in the upper lip. The broad oral retractor, after crossing the intermediate muscle and the 3rd sphincter of the upper lip, gives 2nd sphincter where it appears to be continuous across the middle line. The retractor finally divided into the 1st short sphincter of the upper lip and the 1st and 2nd sphincters of the lower lip, which both the lower lips are continuous across the middle line. The transverse ribs of the gill bar meet dorsally, narrowing sharply toward the ventral surface, so that they are far apart from one another ventrally. The dorsal tubercle is a simple elongated arched stick. The alimentary canal is coiled into a tight nucleus. The gill is long and slender. Stolon runs forward in a straight course on the mid ventral line. There is no outgrowths from the ganglion.

Aggregate ( Fig. 6a , Bottom, 6b): Body length reaches 3.1 mm. Body is oval in form, with short hollow projections anteriorly and posteriorly present, which are slightly asymmetricaly arranged. The test is voluminous, thickly fusiform, soft and smooth with no echination. Five body muscles, all approaching in the mid-dorsal line in two separate groups; MI– MIII are merged in the mid-dorsal region as are MIV –MV; the two groups for the most part touch in the mid-dorsal line. The MV is branched, where its posterior branches on each side passing the base of the atrial siphon; and it unites behind the siphon. The transverse ribs of the gill bar meet dorsally, tapering severely toward the ventral surface, so that they are far-off from one another ventrally. The dorsal tubercle is a simple elongated arched stick. The alimentary canal is coiled into a tight nucleus. The gill is thick and short. Ovary and embryo are situated at MIV ¼.

Remarks. Both solitary and aggregate zooids of this species were found during the sampling of this study. According to Sewell in 1926 (p. 81, fig. 11), in the solitary stage some specimens have ten body muscles instead of nine while van Soest in 1975a (p. 111) stated that specimens from Atlantic Ocean were found to have 8 body muscles instead of nine. This specimen has nine body muscles. Sewell (p. 81, fig. 10, A – D) have also notes the fours variations in the connections of the MI–MIV. The four anterior muscles of this specimen were observed to be closely matching with variation A, where the first MI–MIII muscles are connected together and MIV is approaching MIII. Metcalf in 1918 (p. 95) describes the oral musculature as “consisting of an oral retractor, which give rise to two sphincters of the lower lip and is connected with the 1st sphincter of the upper lip, a broad independent 2nd sphincter of the upper lip, and the intermediate muscle, both of these latter lying internal to the retractor”. From near the dorsal end of the intermediate muscle, a short horizontal muscle runs forwards. Sewell states that in two large Indian Ocean specimens examined by him, there was an additional sphincter in the upper lip. There are 3 sphincters present in the upper lip (p. 80, fig. 9). This specimen resembles of Sewell’s but with a slight different on the upper lip length. The broad oral retractor, after crossing the intermediate muscle and the 3rd sphincter of the upper lip, gives of a 2nd sphincter where it appeared to be continuous across the middle line. The retractor divided into the 1st short sphincter of the upper lip and the 1st and 2nd sphincters of the lower lip, which both the lower lips are continuous across the middle line. A distinct variation is also found in the number of muscular fiber. Van Soest (p. 112) stated the number of fibers could varies from 91–261 fibers. In this specimen, for MI–MIX there is a total of 181 muscle fibers. For aggregate zooids, this specimens closely resemble of Thompson’s rather than the elongated variation collected from Goa by Dr. S.W. Kemp as noted in Sewell (p. 82, fig. 12).

Distribution. Weelia cylindrica is the most common species of Salpidae (van Soest 1975), widely distributed in the Atlantic, Indian and Pacific Ocean. Records from the Atlantic Ocean includes of Dall’s (1871), occurrence on the coast of Rhode Island and Block Island (Metcalf 1918), Sardinera Lagoon of Puerto Rico ( Tokioka & Bhavanarayana 1979), Harbison et al. (1978), Harbison & Campenot (1979), Pomeroy & Deibel (1980), Madin & Cetta (1984), Caron et al. (1989), southeast of Bermuda (Madin et al. 1996), Mid-Atlantic Bight ( Vargas & Madin 2004) 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), Red Sea and Gulf of Suez ( Godeaux 1974; Al-Yamani et al. 2011 & Kannathasan, et al. 2014), Gulf of Aden & Hanish Hill ( Godeaux 1987). Records found from the Pacific Ocean includes (Yount 1954; 1958), Australian Seas ( Herdman 1891 & Thompson 1948), Ritter & Byxbee (1905), Great Barrier Reef lagoon ( Russell & Colman1935), Province of Izu ( Tokioka 1937; 1960) California Current region ( Berner 1967), Florida Current and Gulf of California Mexico ( Madin 1974; Felder & Camp 2009), Bermuda (Madin et al. 1996), European waters (van der Land & van Soest 2001), Mid-Atlantic Bight ( Vargas & Madin 2004), Kaoping Trench, southwestern waters of Taiwan ( Tew & Lo 2005), coast of Panama ( Sutherland 2010), eastern tropical of Mexico ( Hereu et al. 2010), Taiwan waters ( Liao et al. 2013 & Franco et al. 2017), Singapore Straits ( Tey 1967), northwest continental shelf of South China Sea ( Li et al. 2011), Sabah, Borneo of Malaysia. The compilation of previous literature and present data distribution of Weelia cylindrica is shown in Figure 7.

Figures

FIGURE 6a. Weelia cylindrica (Cuvier, 1804). Top, Solitary; Bottom, Aggregate. Br, branchial septum; Dt., dorsal tubercle; End, endostyle; G, ganglion, i.m., intermediate muscle; N, nucleus; o.m., oral musculature.

FIGURE 7. Distribution of Weelia cylindrica (Cuvier, 1804) Red dots: specimen examined by the author; black dots: records based on compilation of previous literature data.