Pseudosyllis brevipennis, GRUBE, 1863

PSEUDOSYLLIS BREVIPENNIS GRUBE, 1863 View in CoL

FIGS 6A – D View Figure 6 , 7 View Figure 7

Trypanosyllis coeliaca Claparede, 1868 , 19(2): 203; San Martın, 2003: 308 – 311, Figs 169, 170.

Type material examined

Neotype: Rovigno , Croatia (45.066667, 13.616667): one specimen mounted on a slide ( ZMB 797 View Materials ), 1912, coll. Heider ( Figs 6A, B View Figure 6 ). GoogleMaps

Other material examined

Rovigno, Croatia: two specimens mounted on slides ( ZMB 7978 View Materials a, ZMB 7978 View Materials b), collection details as for the neotype. Spain, Catalonia : one specimen in 96% EtOH ( MNCN / ADN 9622 ), Port de la Selva (42.3375, 3.203333), Posidonia oceanica , 10 m, 21 September 2004, no collector data GoogleMaps ; two specimens in 96% EtOH ( MNCN 16.01 About MNCN /16041, 16176), Barcelona, Mataro (41.5325, 2.453056), intertidal algae, March 2014, leg. M. Ballesteros GoogleMaps ; one specimen mounted for SEM ( MNCN 16.01 About MNCN /16177) Girona, Cap Falco (42.433333, 3.174722), calcareous algae, 15 September 2011, leg. G. San Martın ( Figs 5C – D View Figure 5 , 8 View Figure 8 ). Spain GoogleMaps , Alboran Sea: one specimen in 96% EtOH ( MNCN 16.01 About MNCN /16040), (42.433333, 3.174722), algae, 42 – 48 m, 21 September 2011, leg. A. Luque and Alboran-INDEMARES Oceanographic Campaign collecting team GoogleMaps ; one specimen in 10% formalin buffered in seawater ( MNCN 16.01 About MNCN / 16178), (35.983333, 2.916667), calcareous algae, 68 – 70 m, 24 September 2011, leg. A. Luque AlboranINDEMARES Oceanographic Campaign collecting team GoogleMaps ; one specimen in 10% formalin buffered in seawater ( MNCN 16.01 About MNCN /16079), (35.878667, 3.077833), calcareous algae, 96 – 100 m, Alboran-INDEMARES Oceanographic Campaign collecting team GoogleMaps .

Diagnosis

Body of medium to small size (up to about 12 mm long) without colour pattern. Short appendages, relatively thick, with few articles ( Figs 6A View Figure 6 , 7A View Figure 7 ). Bidentate chaetae with similar teeth; with spines along margin, distalmost spines reaching the distalmost tooth ( Figs 6B – D View Figure 6 , 7B View Figure 7 ). Proventricle shorter than pharynx, occupying two or three segments ( Fig. 6A View Figure 6 ). Reproduction by single tetraglene stolon (San Martın, 2003).

Description

Neotype, complete specimen: 5 mm long, 0.5 mm wide, 51 chaetigers, without distinct colour pattern ( Fig. 6A View Figure 6 ). Oval prostomium with two pairs of eyes in trapezoidal arrangement, anterior eyes slightly larger ( Figs 6A View Figure 6 , 7A View Figure 7 ); antennae originating on anterior margin of prostomium; long median antenna with about eight articles; lateral antennae shorter, with about six articles. Oval palps shorter, completely separate. Nuchal organs as two densely ciliated semicircular areas, surrounding prostomial lobes ( Fig. 7A View Figure 7 ). Segment 1 slightly smaller than subsequent segments; dorsal enlarged anterior cirri similar in length to antennae, with eight or nine articles; ventral cirri shorter with between four and six articles. Dorsal cirri similar in length to median antenna, with seven or eight articles ( Figs 6A View Figure 6 , 7A View Figure 7 ). Anterior segments with two rows of cilia, reaching cirrophores ( Fig. 7A View Figure 7 ). Between ten and 12 compound bidentate, heterogomph falcigers in anterior and midbody segments, and seven or eight in posterior parapodia. All compound chaetae morphologically similar throughout body, bidentate, with distal tooth slightly larger than proximal one, and spines along margin, most distal ones larger and reaching distal tooth ( Figs 6B – D View Figure 6 , 7B View Figure 7 ). All parapodia with two protruding, acuminate, and thick aciculae ( Fig. 7C View Figure 7 ). Dorsal and ventral simple chaetae not seen. Pharynx through about six segments, with an anterior tooth and a trepan with between eight and ten small teeth ( Fig. 6A View Figure 6 ). Proventricle through three segments, with about 22 muscle cell rows ( Fig. 6A View Figure 6 ). Reproduction by a single cephalous stolon with two pairs of eyes.

Remarks

San Mart � ın (2003) considered that Trypanosyllis coeliaca Claparede, 1868 (type-locality, Naples, W Mediterranean) and Pseudosyllis brevipennis Grube, 1863 (type-locality: Adriatic Sea) were synonymous species. Although the author noted that Pseudosyllis Grube, 1863 had priority over Trypanosyllis Claparede, 1864 ; he considered Pseudosyllis as a nomen dubium, and therefore the species was named as Trypanosyllis coeliaca for stability purposes (see remarks in San Mart � ın, 2003). Our study shows that Trypanosyllis coeliaca , as traditionally considered, belongs to a different genus, more closely related to the genera Xenosyllis , Eurysyllis , and Plakosyllis ( Figs 1 View Figure 1 , 2 View Figure 2 , 5 View Figure 5 ). These results agree with the morphological features: all species included in these four genera share a small body size, short cirri and proventricle, and a trepan with minute teeth, except for Xenosyllis , the trepan of which was secondarily lost. In addition, the species presented a large spine on the chaetae margin that is unique compared with other species of Trypanosyllis . Therefore, we reinstate Pseudosyllis (following ICZN requirements) to include the former Trypanosyllis coeliaca , which should now be considered Pseudosyllis brevipennis , the type and unique species of the genus. One of the specimens examined from the Museum f ur € Naturkunde (Berlin) from the type locality ( Croatia) agrees with the characters described by Grube (1863) and also in the morphological features examined in our specimens. Since the type material is lost, we have designated a neotype for the species (ZMB 7978), but further molecular studies are required to test if the specimens collected in the Spanish coasts are the same species as the specimens from the type locality. The other two specimens examined from the ZMB, identified as Trypanosyllis coeliaca (slides ZMB 7978a and ZMB 7978b), belonging to the same locality, might represent a different species because they have shorter chaetae with a minute proximal tooth and without spines on the margin. Nevertheless, they also share some of the morphological characters defined for Pseudosyllis species, so it will be necessary to sequence and compare specimens of these two morphotypes from Croatia to assess if they are different species. In addition, in order to check the status of Trypanosyllis coeliaca , further molecular studies are required including material from Naples (the type locality). Although Pseudosyllis is currently monotypic, there are also other species traditionally considered within Trypanosyllis that could also belong to Pseudosyllis , as they share the synapomorphies identified for the group. This is the case for Trypanosyllis parvidentata Perkins, 1981 from Florida ( Perkins, 1981) and Trypanosyllis microdenticulata Salcedo-Oropeza , San Martın & Solis-Weiss, 2011, from the southern Mexican Pacific coast (Salcedo-Oropeza et al., 2011). Further molecular analyses are still needed in order to test whether Trypanosyllis parvidentata and Trypanosyllis microdenticulata are more closely related to Pseudosyllis brevipennis than to species within Trypanosyllis , and therefore to establish the status of Pseudosyllis brevipennis s.s.

Type locality

Rovigno, Croatia (Adriatic Sea).

Distribution

Mediterranean Sea.