Diplecogaster Fraser-Brunner 1938

Fricke, Ronald, Wirtz, Peter & Brito, Alberto, 2015, Diplecogaster tonstricula, a new species of cleaning clingfish (Teleostei: Gobiesocidae) from the Canary Islands and Senegal, eastern Atlantic Ocean, with a review of the Diplecogaster-ctenocrypta species-group, Journal of Natural History 50, pp. 731-748 : 734-737

Diplecogaster Fraser-Brunner 1938

Diplecogaster Fraser-Brunner 1938: 415 (type species: Cyclopterus bimaculatus Bonnaterre 1788 by original designation).

Diagnosis

Three and one half gills; gill membranes attached to the isthmus; disc double; dorsal and anal fins normal with strong rays; disc length 3.2 – 5.2 in SL; no spine in subopercular area; 4 – 9 dorsal-fin rays; 3 – 8 anal-fin rays; 20 – 26 pectoral-fin rays; premaxillaries short; maxillaries well forward in position; head lateral-line system with two pores in the lacrymal canal.

Remarks

A total of six valid species is known in this genus; a checklist of the species and an

identification key are presented below.

Within the genus Diplecogaster , two species groups can be distinguished:

– Diplecogaster-bimaculata group: characterised by a moderate number of 4 – 8 rays in the dorsal fin and 3 – 7 in the anal fin (D.- ctenocrypta group: 9 rays in the dorsal fin, 8 rays in the anal fin), and the position of the anus which is situated in the middle between disc and anal-fin origin (D.- ctenocrypta group: situated closer to the analfin origin than to the end of the disc).

Species. D. bimaculata , D. euxinica , D. megalops , D. pectoralis .

Distribution. Mediterranean Sea, Black Sea, eastern Atlantic Ocean, South Africa.

– Diplecogaster-ctenocrypta group (reviewed in the present paper): characterised by a high number of 9 rays in the dorsal fin and 8 in the anal fin (D.- bimaculata group: 4 – 8 rays in the dorsal fin, 3 – 7 rays in the anal fin), and the position of the anus which is situated closer to the anal-fin origin than to the end of the disc (D.- bimaculata group: situated in the middle between disc and anal-fin origin). The species of the group are further distinguished from the Diplecogaster bimaculata , D. euxinica and D. pectoralis in having 14 – 15 caudalfin rays (18 – 21 in D. bimaculata , D. euxinica and D. pectoralis ), and lacking lateral papillae in disc region A (many lateral papillae present in D. bimaculata , D. euxinica and D. pectoralis ), and from D. megalops in 13 – 16 rakers on third gill arch (7 – 9 rakers in D. megalops ).

Species. D. ctenocrypta , D. tonstricula n. sp.

Distribution. Eastern Atlantic Ocean.

Checklist of the species of Diplecogaster

Diplecogaster bimaculata (Bonnaterre [ex Pennant] 1788)

Cyclopterus bimaculatus Bonnaterre [ex Pennant] 1788: 29, pl, 86, figure 355 (seas of England; no types known)

Lepadogaster ocellatus Risso 1810: 74 ( Villefranche-sur-Mer , France; no types known). Lepadogaster reticulatus Risso 1810: 77 ( Nice , France; no types known) .

Lepadogaster mirbeli Risso 1820: 249 ( Nice , France; no types known).

Lepadogaster desfontanii Risso 1827: 275 , pl. 14, figure 39 ( Nice , France; syntypes: MZUF 584-0093 , 10 specimens) .

Lepadogaster latirostris Costa 1840 : Lepadogaster p. 4 ( Naples , Italy; no types known) . Lepadogaster urifasciatus Costa 1840 : Lepadogaster p. 9 ( Gulf of Salerno , Italy; no types known) .

Lepadogaster norvegicus Düben 1845: 112 ( Norway; no types known).

Lepadogaster listellus Nardo [ex Chiereghini] 1847: col. 113 ( Italy; no types known) .

Lepadogaster raninus Nardo [ex Chiereghini] 1847: col. 113 ( Italy; no types known) .

Lepidogaster couchii Saville-Kent 1883: 55 – 56 ( Devonshire and Cornwall, UK; no types known).

Distribution: Mediterranean Sea, north-eastern Atlantic: Norway and Faroes south to Gibraltar.

Diplecogaster ctenocrypta Briggs 1955

Diplecogaster ctenocrypta Briggs 1955: 32 , figure 85 ( Gran Canaria , Canary Islands; holotype: ZMUC P9037 ).

Distribution: Canary Islands.

Diplecogaster euxinica Murgoci 1964

Diplecogaster bimaculata euxinica Murgoci 1964: 229 , figure 1 ( Romania, Black Sea ; holotype: MGAB 55 ).

Distribution. Black Sea.

Diplecogaster melagops Briggs 1955

Diplecogaster megalops Briggs 1955: 31 , figure 84 (off Durban , KwaZulu-Natal, South Africa; holotype: ZMUC P9031 ).

Distribution: South Africa.

Diplecogaster pectoralis Briggs 1955

Diplecogaster bimaculata pectoralis Briggs 1955: 30 , figure 83 ( Gran Canaria , Canary Islands; holotype: ZMUC P9034 ).

Distribution: Canary Islands, Madeira, Azores, Cape Verde Islands.

Diplecogaster tonstricula new species (present paper)

Distribution: Canary Islands, Senegal.

Key to the species of the genus Diplecogaster

1. Dorsal-fin rays 4 – 8; anal-fin rays 3 – 7 ............................................................................................. 2

- Dorsal-fin rays 9; anal-fin rays 8 ......................................................................................................... 5

2. Eye large, eye diameter 0.5 – 0.6 in bony interorbital, 2.3 – 3.6 (mean 3.25) in head length; no ocelli on sides of body; South Africa.............. .............. Diplecogaster megalops

- Eye relatively small, eye diameter 0.7 – 1.2 in bony interorbital, 3.2 – 4.9 (mean 4.2) in head length; at least one ocellus on side of body below pectoral fin; eastern Atlantic, Mediterranean Sea and Black Sea ................................................................................................................. 3

3. Snout length 3.7 – 7.7 in head length; upper attachment of axial, dermal flap opposite pectoral-fin rays 10 – 19 (mean 18); principal caudal rays 12 – 14 .................................................................................................................... Diplecogaster euxinica

- Snout length 3.3 – 3.8 in head length; upper attachment of axial, dermal flap opposite pectoral-fin rays 10 – 13 (mean 12); principal caudal rays 9 – 12 ............................................... 4

4. Pectoral-fin rays 21 – 24; caudal – peduncle depth 1.2 – 1.5 (mean 1.3); eye diameter 3.7 – 4.9 (mean 4.1) in head length...................................... ...................................... Diplecogaster bimaculata

- Pectoral-fin rays 25 – 26; caudal – peduncle depth 1.0 – 1.2 (mean 1.1); eye diameter 3.2 – 3.9 (mean 3.6) in head length................................................................................ Diplecogaster pectoralis

5. Pelvic disc with lateral papillae in region A; disc region B with 5 rows of papillae; mandibular canal with 1 pore; principal caudal-fin rays 16; interorbital distance 5.4 in head length; distance between disc and anus 19% of SL ........................ Diplecogaster ctenocrypta

- Pelvic disc without lateral papillae in region A; disc region B with 2 rows of weak papillae; mandibular pores missing; principal caudal-fin rays 14 – 15; interorbital distance 4.1 – 4.6 in head length; distance between disc and anus 14 – 17% of SL ................................................................................................... Diplecogaster tonstricula n. sp.