Caprella tuberculata Bate and Westwood, 1868

Guerra-García, J. M. & Takeuchi, I., 2002, The Caprellidea (Crustacea: Amphipoda) from Ceuta, North Africa, with the description of three species of Caprella, a key to the species of Caprella, and biogeographical discussion, Journal of Natural History 36 (6), pp. 675-713 : 698-704

Caprella tuberculata Bate and Westwood, 1868

(®gures 17±20)

Caprella tuberculata GueÂrin, 1836 , pl. 28, ®gure 1; Goodsir, 1842: 188 ±189, pl. 3, ®gures 6±7; Bate and Westwood, 1868: 68 ±70; Mayer, 1882: 56 ±57, ®gures 15±16; Chevreux and Fage, 1925: 460 ±461, ®gure 437; Schellenberg, 1942: 230 ±239, ®gure 199.

Caprella acanthifera: Bate, 1862: 366 , pl. 57, ®gure 2.

Material examined. 2B: ®ve males, six females; 15D: four males, six females, four ovigerous females, two juveniles.

Diagnosis

Head with a short and acute rostrum in males, and small round protuberance in females. Except the ®rst, all body pereonites with strong and numerous dorsal tubercles. Males with a pair of lateral tubercles on pereonite 5. Pereonites 1 and 2 elongated in male, pereonite 2 with plumose setae in males. Palm of the propodus of gnathopod 2 in males with large thumb-like protuberance de®ning the palm, and with long and dense, plumose setae. Anterior surface of basis and propodus also with plumose setae. Pereopods 5 and 6 with a pair of proximal grasping spines. Pereopod 7 with four grasping spines in males (in clusters of 2-1-1) and three in females (2-1).

Material examined

Male `a’ from the hydroid Sertularella gayi Lamouroux (35ss55¾ 20 ² N, 5ss22¾W). Depth 28 metres, July 1999, coll. Jose Manuel Guerra-GarcõÂa. Female `b’ found together with male`a’. Other specimens: four males, ®ve females collected together with male`a’; four males, ten females and two juveniles on seaweed Dilophus spiralis Hamel (35ss54¾N, 5ss16¾ 35 ² W), August 1999, coll. Juan RodrõÂguez. Male `a’, female`b’ and another three specimens are deposited in the Museo Nacional de Ciencias Naturales de Madrid, Spain (No. MNCN 20.06 /4649) , the remaining specimens are in the Laboratorio de BiologõÂa Marina, Universidad de Sevilla , Spain .

Locality Ceuta, North Africa , Mediterranean (35ss55¾ 20 ² N, 5ss22¾W; 35ss54¾N, 5ss16¾ 35 ² W) .

Redescription.

Male`a’

Body length. 5.9 mm.

Lateral view. Head with a short, acute and curved rostrum. Except the ®rst one, all pereonites with tubercles following the formula 0-2.1-2.1-1.2.1- 2 (lateral).2.2- 4-2.2. Pereonites 1 and 2 elongated; pereonite 2 bearing long plumose setae dorsally and ventrally.

Gills. Oval, length ca twice width.

Antennae. Antenna 1 with the same length as cephalon and pereonite 2 together; peduncular articles setose; ¯agellum with 11 articles. Antenna 2 about half length of antenna 1; peduncular articles 3 and 4 carrying six pairs of long, serrated setae; ¯agellum two-articulate, setose.

Mouthparts. Upper and lower lip similar to those in Caprella ceutae n. sp. Pars incisiva and lacinia mobilis with ®ve teeth on each; left mandible with three pectinate setae and the right with two; a row of short and ®ne setae between the pectinate setae and the molar process. Maxilla 1 outer lobe with seven serrated spines distally; article 2 of palp with eight distal setae and a row of four lateral setae. Inner lobe of maxilla 2 shorter than outer, with 12 apical setae; outer lobe with nine apical setae. Inner plate of maxilliped shorter and a little wider than outer plate, with seven plumose setae and two teeth; outer plate with long simple setae and three teeth; article 2 and 3 of palp with long setae; article 4 with rows of setulae on grasping margin.

Gnathopods. Merus and carpus of gnathopo d 1 with row of four setae on posterior margin; propodus with a pair of proximal grasping spines; palm of propodus with a few setae; dactylus partially serrated on the inner margin. Gnathopod 2 inserted on the posterior part of the pereonite; basis one-third length of pereonite 2, with carina and several plumose setae on anterior surface; ishium, merus and carpus rounded; merus about 1.5 times larger than ischium; carpus very short, length ca one-®fth of merus; palm of propodus de®ned proximally by a large, thumb-like protuberance and distally by a round projection; between these two projections, the palm of the propodus is very concave, covered with a mixture of dense ®ne plumose and simple setae; dorsal surface of propodus also with plumose setae; dactylus with medial protuberance and plumose setae.

Pereopods. Pereopods 5, 6 and 7 increasing in length respectively; palm of propodus concave; a pair of proximal grasping spines on pereopods 5, 6 and 7; on pereopod 7, two additional grasping spines, four in total.

Abdomen. With a pair of appendages, a pair of lateral lobes and a single dorsal lobe; appendage two-articulate, the two articles of each appendage rounded and approximately the same size; both articles carrying three setae; distal article serrated on the apical margin; lateral lobes carrying four simple setae and dorsal lobe with two plumose setae. Penes median, slender, length ca three times width.

Female`b’

Body length. 4.1 mm. Head with a short dorsal protuberance in the middle. Pereonite 1 and 2 not elongated; tubercle formula on pereonites 0-1.2.1-2-1.2.1 - 2-4-2.2, pereonite 5 lacking lateral tubercles; pereonite 2 without setae. Peduncular articles of antenna 1 scarcely setose; ¯agellum of antenna 1 with eight articles. Gnathopod 2 inserted on anterior half of pereonite 2; palm de®ned by two small teeth instead of thumb-like protuberance, without distal projection at the dactylar hinge; basis, propodus and dactylus without ®ne, plumose setae. Pereopod 7 propodus with three grasping spines. Anterior brood lamellae setose all round, posterior pair not setose. Abdomen with a pair of lateral lobes which carry two setae and a dorsal lobe with two plumose setae.

Remarks

As McCain and Steinberg (1970) pointed out, the nomenclature of this species is one of the most confused among the caprellid species. Indeed, Mayer (1882) considered that the specimens described by GueÂrin (1836) and Goodsir (1842) were not C. tuberculata . Stebbing (1888) mentioned that GueÂrin’s C. tuberculata could be a synonym of C. scaura . The description of C. tuberculata given by GueÂrin (1836) is quite brief.

The specimens found in Ceuta are in agreement with the description of C. tuberculata given by Bate and Westwood (1868) for Atlantic specimens. However, we have observed several diOEerences. Following the descriptions of Bate and Westwood (1868), Chevreux and Fage (1925) and Harrison (1944) the most striking diOEerence between C. tuberculata of Bate and Westwood and C. tuberculata found at Ceuta is the size; males of Caprella tuberculata from Ceuta do not exced 5.9 mm (although we have observed only nine adult males), while specimens from British and French coasts ( Bate and Westwood, 1868) usually reach 15 mm at adulthood. Caprella tuberculata from Ceuta is also distinguished from Atlantic specimens as follows: (1) males from Ceuta have a short and round rostrum on the head while Atlantic specimens have a very short, central, dorsal spine; (2) male`a’ and female`b’ from Ceuta have tubercles following the formula (0-2.1-2.1-1.2.1- 2 (lateral).2.2- 4-2.2 in male, and 0-1.2.1-2-1.2.1-2-0-2. 2 in female). These tubercles are always present in the other specimens examined but some small tubercles may occur depending on the individuals. There is no speci®c formula for tubercles in descriptions of Atlantic specimens; (3) in C. tuberculata from Ceuta the propodus of pereopod 7 has four grasping spines in males and three in females, while there is only a single pair of grasping spines in Atlantic specimens (both male and females); (4) the posterior brood lamella are not setose on the posterior edges in females from North Africa; a setose margin is present in Atlantic specimens.

Before this study, Caprella tuberculata had been found on the British and French coast but also at Santander, northern Spain ( Chevreux and Fage, 1925). Marques and Bellan-Santini (1985) also reported 27 specimens of C. tuberculata from between Peniche and Arrabida (Portuguese Atlantic coast). An extensive comparative study between Atlantic individuals of C. tuberculata and the specimens of the Strait of Gibraltar would be necessary in order to elucidate whether the above diOEerences are intra-speci®c or inter-specic. Recently, a detailed comparison has been successfully conducted for the species complex Caprella acanthifera ( Krapp-Schickel and Vader, 1998) collected from Atlantic and Mediterranean waters.