Trypanosyllis krohnii, CLAPAREDE, 1864

Álvarez-Campos, Patricia, Giribet, Gonzalo, San Martín, Guillermo, Rouse, Greg W. & Riesgo, Ana, 2017, Straightening the striped chaos: systematics and evolution of Trypanosyllis and the case of its pseudocryptic type species Trypanosyllis krohnii (Annelida, Syllidae), Zoological Journal of the Linnean Society 179 (3), pp. 492-540 : 520-522

TRYPANOSYLLIS KROHNII CLAPAREDE, 1864 ;

FIGS 4B , 10A , 11

Type material examined

Neotype. France, Banyuls-sur-Mer (42.483333, 3.133333): one specimen in 96% EtOH ( MNCN ADN/ 9623 ), Harbour on docks, snorkelling, epifauna on mussels (i.e. hydroids, sponges), 19 April 2001, no collector data ( Fig. 9A ).

Other material examined

Spain, Catalonia: one specimen in 96% EtOH ( MNCN 16.01 /16187), Barcelona, Mataro (41.5325, 2.453056), intertidal algae, March 2014, leg. M. Ballesteros ; one specimen in 96% EtOH ( MNCN 16.01 /16066), Girona, Cap de Creus (42.320278, 3.320556), Petrosia sp. , 16 m, 16 September 2011, leg. G. San Martın ; one specimen mounted for SEM ( MNCN 16.01 /16186), collection data as for MNCN 16.01/16066; four midbody parts ( MNCN 16.01 / 16188), collection data as for MNCN 16.01/16066 .

Morphologically similar species examined

Italy: Trypanosyllis zebra , one specimen ( ZMB Q4428 ), Lesina (41.766667, 15.433333), 1874, leg. Grube. Lessina coll. Grube.

Diagnosis

Colour pattern in preserved specimens as brown transverse stripes across anterior and midbody parts, one close to anterior end of segment and the other in middle of segment ( Figs 4B , 10A ). All stripes similar in length, reaching parapodia ( Figs 4B , 10A ). Large anterior cirri with about 42 articles (n = 5); dorsal cirri alternating long (30 – 32 articles) and short (20 – 22 articles).

Description

Neotype incomplete, 8 mm long, 1.5 mm wide, 83 chaetigers. Long dorsoventrally flattened body ( Figs 10A , 11A ). Colour pattern as two thin, brown, transverse stripes across limit of anterior and midbody segments ( Fig. 10A ). Some specimens with purple pigmentation remaining on anterior and dorsal cirri ( Fig. 4B ). Oval prostomium with two pairs of eyes in trapezoidal arrangement ( Fig. 10A ); antennae originating on anterior margin of prostomium, long median antenna with about 30 articles; lateral antennae slightly shorter, with about 25 articles ( Fig. 10A , 11A, B ). Oval palps shorter than prostomium, completely separated. Nuchal organs as two densely ciliated semicircular areas, extending on prostomium and surrounding prostomial lobes. In addition, ciliary bands on dorsum of anterior and midbody segments and parapodia ( Fig. 11C ). Segment 1 slightly smaller than subsequent segments; dorsal enlarged anterior cirri longer than antennae, with about 42 articles, longer than ventral cirri, with about 35 articles Dorsal cirri alternating long (30 – 32 articles) and short (20 – 22 articles). Ventral digitiform cirri, reaching edge of parapodia. Parapodia with two anterior, digitiform lobes. Compound bidentate, heterogomph falciger chaetae, about 15 – 17 on anterior parapodia, 13 – 15 on midbody and 12 – 14 on posterior ones. All chaetae similar throughout body, with both teeth similar in length and serrated margin ( Fig. 11D – G ); all parapodia with dorsal chaetae with longer blades and very short spines on the margin ( Fig. 11D, F ), and ventral bidentate chaetae, shorter than ventral chaetae, with minute spines on the margin of anterior and midbody chaetae ( Fig. 11E ), and almost smooth on posterior parapodia ( Fig. 11G ). Three or four anterior straight aciculae, all distally blunt; two or three midbody and posterior straight, distally pointed aciculae thicker than anterior aciculae. Dorsal and ventral simple chaetae not seen. Pharynx running through 11 segments. Proventricle running through 13 segments, with about 40 muscle cell rows.

Remarks

Trypanosyllis , together with the species Trypanosyllis krohnii , were described by Claparede (1864) from Port-Vendres ( France). Four years earlier, Syllis zebra Grube, 1860 was described from the Adriatic Sea, and Marenzeller (1874) later placed it in Trypanosyllis because it presented a trepan. In 1879, Langerhans synonymized Trypanosyllis krohnii with Trypanosyllis zebra on the basis of the original descriptions, without studying the type specimens (subjective synonymy, ICZN, article 61.3). All subsequent authors followed this synonymy, probably because of the similarity in the striped coloration found in both species. Many years later Hartman (1959) designed Trypanosyllis zebra as the type species of the genus by subsequent designation (ICZN, article 69.1), and since then all the authors except Day (1967) considered this designation as valid (e.g., Imajima, 1966; Uebelacker, 1984; San Mart � ın, 2003). Our study found that Hartman’s designation is in fact not valid, because Claparede (1864) described the genus Trypanosyllis and its monotypic type species Trypanosyllis krohnii (ICZN, art 68.3), which is a valid species. Lineage 6, which inhabits the same geographical areas as the type species, presented enough distinctive morphological features to separate them, such as the colour pattern, the length of the dorsal cirri, and the body width ( Fig. 10A, I ; Table 3). In addition, the comparative material from the Adriatic deposited in the ZMB, which was collected in 1874 and identified by Grube as Syllis zebra , also differed from lineage 6 in the same characters ( Fig. 10C, I ; Table 3), but was slightly more similar to Trypanosyllis krohnii than lineage 6 ( Fig. 10A, C ; Table 3). The ZMB specimen did not fully agree with the original description of Trypanosyllis zebra Grube (1860) , mainly because of the huge size of the holotype described by Grube ( Table 3), and therefore we prefer not to designate it as the neotype of Trypanosyllis zebra . Likewise, even though this ZMB specimen is similar to Trypanosyllis krohnii , we cannot synonymize them because we have not sequenced this material. Therefore, until new material of striped Trypanosyllis from the Adriatic is collected for further sequencing, we will regard our specimens in lineage 6 as Trypanosyllis sp. 2 .

Nevertheless, here we conclude that Trypanosyllis krohnii is not a synonym of Trypanosyllis zebra , but a valid and well-defined species distributed at least in the Gulf of Lion and along the north-west coast of Spain ( Tables 1 and 3). In the present study we re-describe the type species of the genus, designating a neotype (as the type material is lost) following the ICZN requirements. The studied specimens agree with the original description, except for the colouration, which Claparede (1864) described as violet. As we have observed remnants of violet pigmentation in the anterior and midbody cirri of some specimens ( Fig. 4B ), we conclude that the coloration differences may be the result of preservation methods. Our results also suggest that the species is distributed in the same area (Gulf of Lion) as Trypanosyllis sp. 2 , but inhabiting different bathymetric ranges, with Trypanosyllis krohnii occurring in more shallow waters ( Table 3). Marion & Bobretzky (1875) reported Trypanosyllis krohnii from the Gulf of Marseille, noting that specimens collected in shallow waters presented body coloration and length of cirri that differed considerably from those of specimens collected in deeper waters, although they considered both as the same species. Our examination agrees with their observation, and thus we conclude that there is enough molecular, morphological, and ecological evidence to consider them as two different species.

Type locality

Banyuls-sur-Mer, France (North-Western Mediterranean Sea).

Distribution

Gulf of Lion (Mediterranean Sea), including the Cap de Creus, in the north-eastern coast of Spain (Girona).

Figures

Figure 4. Pseudocryptic speciation within Trypanosyllis s.l. obtained from the concatenated data set of nuclear and mitochondrial genes (28S rRNA, 18S rRNA, 16S rRNA, and COI). A, Bayesian gene tree with posterior probabilities (>0.90) on each node. Red branches indicate the well-supported (>0.90) lineages found in the species delimitation analyses. B, world map showing the location of the new pseudocryptic species (microscope pictures of ethanol-fixed material) recovered after species delimitation analysis. Neotype of Trypanosyllis krohnii (MNCN/ADN 9623), holotypes of Trypanosyllis taboadai sp. nov. (MNCN 16.01/16087), Trypanosyllis luquei sp. nov. (SIO A5005), Trypanosyllis leivai sp. nov. (MNCN 16.01/16082), Trypanosyllis californiensis sp. nov. (SIO A5008), and Trypanosyllis kalkin sp. nov. (MNCN 16.01/16058), are shown.

Figure 9. Scanning electron micrographs of Trypanedenta gigantea comb. nov.: A, anterior part (MNCN 16.01/ 16505); B, prostomium (MNCN 16.01/16505), arrow points to the nuchal organs (no); C, detail of dorsal cirri (MNCN 16.01/16506); D, detail of the trepan pharynx in apical view, arrow points to the trepan (t) (MNCN 16.01/16501); E, pharynx and proventricle (MNCN 16.01/165052); F, anterior chaetae (MNCN 16.01/16505); G, midbody chaetae, arrow points to four protruding aciculae (a; MNCN 16.01/16506); H, posterior chaetae, arrow points to two protruding aciculae (a; MNCN 16.01/16508).

Figure 10. Light microscopy images of the anterior of Trypanosyllis s.s. species: A, Trypanosyllis krohnii neotype (MNCN/ADN 9623); B, Trypanosyllis aeolis (MNCN 16.01/16039); C, Trypanosyllis zebra (ZMB Q4428); D, Trypanosyllis luzonensis comb. nov. (AM W.47275); E, Trypanosyllis taboadai sp. nov. holotype (MNCN 16.01/16087); F, Trypanosyllis luquei sp. nov. holotype (SIO A5005); G, Trypanosyllis leivai sp. nov. holotype (MNCN 16.01/16082); H, Trypanosyllis californiensis sp. nov. holotype, live specimen (SIO A5008); I, Trypanosyllis sp. 2 (MNCN 16.01/ 16065); J, Trypanosyllis kalkin sp. nov. holotype (MNCN 16.01/16058).

Figure 11. Scanning electron micrographs of Trypanosyllis krohnii (MNCN 16.01/16186): A, anterior part; B, prostomiun; C, detail of ciliary bands in midbody dorsal segments and parapodia; D, anterior dorsal chaeta; E, anterior ventral chaetae; F, posterior dorsal chaeta; G, posterior ventral chaetae.