Timarete caribous (Grube, 1859)

Çinar, Melih Ertan, 2009, Alien polychaete species (Annelida: Polychaeta) on the southern coast of Turkey (Levantine Sea, eastern Mediterranean), with 13 new records for the Mediterranean Sea, Journal of Natural History 43 (37 - 38), pp. 2283-2328 : 2305-2307

Timarete caribous (Grube, 1859)

( Figure 7 )

Cirrhatulus caribous Grube 1859: 106 .

Cirriformia caribous ; Kirkegaard 1981: 264–265, fig. 1

Timarete caribous ; Petersen 1999: 116.

Material examined

ESFM-POL/2005-1129 , 17 September 2005, K13, 0.2 m, on tyres, 3 specimens .

Additional material examined

ZMUC-POL-260, 3 Syntypes, 18 September 1845, St Croix, Caribbean Sea.

Description

Largest specimen complete, 27 mm long, 2.5 mm wide, with 153 chaetigers. Body elongated, thickened throughout with short, crowded segments, tapering posteriorly, with a shallow ventral groove ( Figure 7A ). Background colour pale brownish, with black pigmentations on anteroventral body surfaces; tentacular filaments and branchiae pale brownish ( Figure 7A,B ). Prostomium triangular, broad, bluntly pointed on anterior margin; eyes absent. Peristomium short, about 1.5 times longer than prostomium, with two distinct annulations. Tentacular filaments present on chaetigers 4 and 6, formed in two distinct groups, each having 32 filaments. Branchiae present from chaetiger 1 to posterior segments; branchiae located just dorsal to notopodia from chaetigers 1 to 10; branchiae gradually moving to dorsal midline of body from chaetiger 10 to 50 and located in midline from chaetiger 50 to posterior end. Notopodia and neuropodia widely separated, poorly developed. Parapodia with capillary chaetae and acicular spines. Chaetiger 1 with only capillary chaetae, numbering six on notopodia and 10 on neuropodia, measuring c. 650 µm long. Acicular spines first present on notopodium of chaetiger 30, and on neuropodium of chaetiger 16. In anterior chaetigers (between chaetiger 16 and 50), acicular spines associated with capillary chaetae. On chaetiger 30, notopodia with three acicular spines and six capillary chaetae, neuropodia with three acicular spines and one capillary chaeta. Acicular spines in anterior parapodia, brownish, slightly sigmoid, c. 100 µm long. After chaetiger 50, neuropodia with only acicular spines and after chaetiger 55 to pygidium, acicular spines numbering one on each neuropodia ( Figure 7C ). On chaetiger 75, notopodia with three acicular spines and three capillary chaetae; neuropodia with only one acicular spine; acicular spines measuring 140 µm on notopodia, 300 µm on neuropodia; capillary chaetae on notopodia measuring 540 µm. Acicular spines on neuropodia of middle parapodia sigmoid and dark brownish. On posterior parapodia, notopodia with three acicular spines (100 µm long) and one capillary chaeta (360 µm long) ( Figure 7D ); neuropodia with one acicular spine (160 µm long) ( Figure 7E ). Pygidium somewhat triangular; anal opening placed dorsally.

Reproduction

One specimen of this species has oocytes in its coelomic cavity, measuring 80–100 µm in diameter.

Remarks

The Mediterranean specimens coincide with the syntypes of Timarete caribous deposited in ZMUC. However , there are some slight differences between Mediterranean and Caribbean specimens that could be the result of the difference in the size of worms. The largest syntype (34 mm long, 3 mm wide, with 176 chaetigers) is longer than the largest Mediterranean specimen. The neuropodial hooks are first present on chaetiger 16 in both specimens, but notopodial hooks are commenced on chaetiger 30 in the Mediterranean specimen, on chaetiger 40 in the Caribbean specimen. The neuropodia are represented by only one sigmoid hook after chaetiger 50 in the Mediterranean specimen, whereas the solitary neuropodial hook can be seen after chaetiger 100 in the Caribbean Sea. The morphology of chaetae is similar in both specimens .

In the Mediterranean, T. caribous might have been overlooked or confused with the native species T. filigera (Delle Chiaje, 1828) . Therefore, the previous reports of T. filigera , particularly from the harbour environments, should be checked to ascertain the real distribution pattern of this species in the Mediterranean. The main difference between these species is that the middle and posterior neuropodia of T. caribous have only one large, sigmoid dark brown hook, whereas those of T. filigera have at least three relatively thin, pale brownish hooks associated with one or two capillary chaetae. The other Timarete species reported from the Mediterranean Sea is T. punctata (Grube, 1859) , which was considered to be a Lessepsian migrant (Çinar 2007). Timarete punctata mainly differs from T. caribous in having black irregular spots on body surface, tentacular filaments and branchiae (absent in T. caribous ).

Distribution

This species was previously known from the western and central Atlantic Ocean ( Kirkegaard 1981). It could have been introduced to the Mediterranean via ballast waters of ships, as it was found only on a used tyre submerged in the fishing harbour at Karaduvar (Mersin Bay), which is very close to one of the largest commercial harbours (Mersin Harbour) in Turkey .

Figures

Figure 7. Timarete caribous: (A) whole body, dorsolateral view (ESFM-POL/2005-1129), (B) anterior part, ventral view, (C), middle part, ventral view, (D) acicular spines and capillary chaeta on notopodium of chaetiger 110, (E) acicular spine on neuropodium of chaetiger 110. Scale bars: (A) 2.5 mm, (B) 1.30 mm, (C) 1.80 mm, (D) 100 µm, (E) 172 µm.