Condyloderes clarae, Zotto & Neuhaus & Yamasaki & Todaro, 2019

3.2. Condyloderes clarae View in CoL sp. nov.

http://zoobank.org/A8E22442-31E0-4A5C-A9DD- CA1E62880B56.

( Figs. 5 View Fig , 8 View Fig ‾ 12; Tables 1, 2, 4; TableS2).

Condyloderes sp. 2 (Ligurian Sea) — Dal Zotto & Todaro (2016).

3.2.1. Diagnosis

Condyloderes with two lateral rows of condyles in broader placids, two apical and three basal condyles in midventral placid, two apical and two large basal condyles in remaining broader placids, and two basal condyles in narrower placids, apart from the two neighbouring the midventral placid with only one basal condyle; longitudinal rows of cuticular hairs regularly arranged on trunk segments 1 ‾ 10, fewer and with shorter hairs on segment 10; acicular spines lateral accessorily on segments 1 and 11, lateroventrally on segments 2 ‾ 9 (on segment 10 in females only), laterodorsally on segment 10 in males only; cuspidate spines ventrolaterally slightly displaced ventromedially on segment 5, ventrolaterally on segment 8, and lateral accessorily on segment 9; ventromedial appendages on segments 5 ‾ 7 in females only; type-6 sensory spots paradorsally on segments 1 and 7, sublaterally on segments 3 and 6, and ventromedially on segment 8.

3.2.2. Examined material

Holotype: female, mounted as glycerol-paraffin slide on a Cobb aluminium frame, ZMB 11826 . Paratypes: two males, mounted as glycerol-paraffin slide on a Cobb aluminium frame, ZMB 11827 and ZMB 11828 mounted as glycerol-paraffin slide on a Cobb aluminium frame. Non-type: one juvenile ZMB 11829 , mounted as glycerol-paraffin slide on a Cobb aluminium frame. One non-type male ZMB 11830 mounted on aluminium stub for scanning electron microscopy. Information on localities of the type and non-type material is reported in Table 1.

3.2.3. Type locality

Mediterranean Sea, Ligurian Sea , Tuscany , off Livorno ( Leghorn ), 43 Ǫ 37 Į 35 ĮĮ N, 009 Ǫ 59 Į 18 ĮĮ E, 112 m depth, sandy mud.

3.2.4. Etymology

The species is named after the second daughter of the first author, Chiara, and follows the Latinized wording Clara and its genitive Clarae .

3.2.5. Description

The description refers to female. No variation was observed in the examined material except for the midventral placid (see below). See chapter “3.2.6. Sexual dimorphism” for male characters that differ from female ones. Figures and tables show both male and female characters (see figure and table legends). The analysed adult specimen consists of head, neck, and 11 trunk segments ( Figs. 8 View Fig , 9A, B View Fig , 10A View Fig , and 11A View Fig ). See Table 2 for a summary of spine and sensory spot position, and Table 4 for measurements and dimensions.

Head. The head is made up of a retractable mouth cone and an introvert ( Fig. 10B View Fig ). The introvert has six rings of scalids and one ring of trichoscalids. Ring 01 bears 10 primary spinoscalids, consisting of a sheath-like basis and an elongated distal part. Rings 02 to 05 bear 5, 15, 15, and 15 scalids, respectively. The number of scalids in ring 06 is more than 12, even though the exact number could not be detected because those in sectors 3, 5, 7, and 9 could not be observed. Generally, the scalid arrangement appeared very similar and is most likely identical to C. agnetis sp. nov. ( Fig. 5 View Fig ). The posterior part of the introvert is characterized by 14 elongated and fringed trichoscalids ( Figs. 11C View Fig and 12F View Fig ). Apair of filamentous appendages is attached anteriorly to each trichoscalid. These structures are thinner than the scalids and do not show external sculpturing ( Fig. 10B View Fig ).

Neck. The neck consists of 16 placids, having irregular, knobby surfaces (condyles), varying in number between narrower and broader placids ( Figs. 9C View Fig , 10D View Fig , and 11C View Fig ). Abroader midventral placid is neighboured by two narrower placids, and from thereon a broader and a narrower placid alternate. The midventral placid shows 5 ‾ 6 condyles arranged in an apical lateral row with two condyles and a basal lateral row with three condyles in the female holotype and in the male allotype ( Fig. 10D View Fig ), whereas the male mounted for SEM reveals four basal condyles ( Fig. 11C View Fig ). The remaining broader placids have two apical and two basal condyles; the basal condyles are very large and seem to possess apically three smaller condyles ( Fig. 11C View Fig ). The narrow placids have two basal condyles, apart from the two closest to the midventral placid, which bear only one basal condyle ( Fig. 11C View Fig ; TableS2).

Trunk. The trunk is divided into 11 segments. It appears triangular in cross-section, with the tergosternal junctions located along two of the lateroventral angles.

Segment 1 is formed by a closed cuticular ring and shows a broad and squared midventral indentation, because the free flap is missing ( Figs. 8A View Fig , 9D View Fig , 10D View Fig , and 11C View Fig ). This segment is characterized by a middorsal hirsute spine and two acicular spines placed in lateral accessory position ( Fig. 9D View Fig ). The middorsal spine from this segment through segment 10 is located posteriorly on a segment and originates from a sclerotized anterior keel on a trunk segment; the free flap is missing where a spine inserts ( Fig. 9B View Fig ). Minute cuticular hairs are located along the anterior part of the segment. Paired type-6 sensory spots are located anteriorly in subdorsal, laterodorsal, midlateral, sublateral, and ventromedial position ( Figs. 9C, D View Fig , 10D View Fig , 11C View Fig , and 12D View Fig ). Similar to the following segments, the posterior margin of the segment is straight, and shows a free flap overlapping the subsequent segment and terminating in a primary pectinate fringe ( Figs. 11D View Fig and 12C View Fig ). The free flap is interrupted where the spines originate and ventrolaterally to midventrally. This condition is repeated through segments 2 to 11 except for the ventral lack of the free flap ( Figs.11D View Fig and 12C View Fig ), even if the teeth of the primary pectinate fringe are shorter and smaller on segments 10 and 11. Very long cuticular hairs are arranged in longitudinal rows of three to five each originating from the anterior to the central part of the segment and continuing beyond the segment's posterior edge on the dorsal side ( Fig. 9F View Fig ). There are approximately 18 ‾ 20 rows. In addition, many irregularly arranged cuticular hairs are present midventrally and ventrolaterally from anterior to posterior.

Segment 2 consists of a tergal and two sternal plates. The same condition is repeated through segments 3 to 10. The segment bears a middorsal spine and two lateroventral acicular spines. Pairs of type-6 sensoryspots are located in subdorsal, laterodorsal, midlateral, sublateral, and ventromedial position ( Figs. 9D View Fig , 11C, Dand View Fig 12D View Fig ). The subdorsal and sublateral sensoryspots are placed posteriorly, whereas the laterodorsal, midlateral and ventromedial are located more medially on the segment ( Fig. 11D View Fig ). Long cuticular hairs arranged in longitudinal rows of normally six each originate from the middle part of the segment and continue beyond the segment's posterior edge. There are approximately 6 ‾ 7 rows on each sternal plate and 24 ‾ 26 on the tergal plate. These rows are absent midventrally, paraventrally and midlaterally ( Figs. 9D View Fig ‾ F, 10E, 11A—B, D—E, and 12A—B, D—E).

Segment 3 bears a middorsal spine and two lateroventral acicular spines. Two pairs of type-6 sensory spots are placed posteriorly in subdorsal and sublateral position ( Fig.12D, E View Fig ). No ventral sensory spot was detected ( Fig. 11D View Fig ).

Segment 4 is characterized by one middorsal spine and two lateroventral acicular spines. Pairs of type-6 sensory spots are placed paradorsally, laterodorsally, and ventromedially ( Figs. 10E View Fig , 11B, D View Fig , and 12E View Fig ).

Segment 5 shows one middorsal spine, two lateroventral acicular spines, and two ventrolateral cuspidate spines slightly displaced ventromedially ( Figs. 8A View Fig , 9D View Fig , 10E View Fig and 11B View Fig ). The cuspidate spines are located next to the edge of the ventromedial position ( Figs. 9A, Dand View Fig 10E View Fig ). Asingle pair of type-6 sensory spots is located laterodorsally ( Fig. 12E View Fig ). No ventral sensory spot was detected. The female bears ventromedial appendages on this segment ( Fig. 9D View Fig ).

Segment 6 bears one middorsal and two lateroventral acicular spines. Pairs of type-6 sensory spots are located paradorsally, midlaterally, and ventromedially ( Figs. 8A View Fig , 11B View Fig , and 12A View Fig ). The female bears ventromedial appendages on this segment ( Fig. 9D View Fig ).

Segment 7 has one middorsal spine and two lateroventral acicular spines. Apair of type-6 sensory spots is located laterodorsally and a second pair of this same type of sensory spots is placed ventromedially ( Figs. 11B View Fig and 12A View Fig ). The female bears ventromedial appendages on this segment ( Fig. 9D View Fig ).

Segment 8 bears one middorsal spine, two lateroventral acicular, and two ventrolateral cuspidate spines ( Fig.12A View Fig ). These latter spines are noticeably longer than other cuspidate spines ( Figs. 9B View Fig , 10C View Fig , and 11A—B View Fig ; Table 5). Pairs of type-6 sensory spots are located in paradorsal, laterodorsal, and ventromedial position ( Figs. 11B View Fig and 12A View Fig ).

Segment 9 has one middorsal spine, two lateroventral acicular spines, and two lateral accessory cuspidate spines ( Figs. 9B View Fig , 10C View Fig and 11A, E View Fig , 12B, C View Fig ). Pairs of type-6 sensory spots are placed paradorsally, laterodorsally, and ventromedially ( Figs. 11E View Fig and 12B, C View Fig ). Astructure with cuticular papillae is present in sublateral position. We assume that this character represent the protonephridial opening ( Fig. 12B View Fig ‾ C). Ventromedial areas of micropapillae are absent.

Segment 10 is characterized by a rather long middorsal spine ( Figs. 9B View Fig and 12B View Fig ). Apair of paradorsal type-6 sensoryspots is present. The teeth of the primary pectinate fringe are shorter and smaller than on segments 1 to 9 ( Fig. 11E View Fig ). Cuticular hairs shorter, and arranged in fewer rows. The female bears two lateroventral acicular spines on this segment ( Fig. 9B View Fig ).

Segment 11 is formed by one tergal and one sternal plate. The latter shows a midventral to paraventral cuticular thickening, appearing optically separated from the remaining plate because of a paraventral fold in the cuticle ( Figs. 9E View Fig and 11E View Fig ). This segment bears a midterminal spine and two elongated lateral terminal accessory spines each with two thin areas in the basal parts ( Figs. 9A, B View Fig , 10A View Fig , 11A, E View Fig , and 12B View Fig ). Two type-3 sensoryspots, composed of a conical base and terminal cuticular papillae, are placed centrally on the segment in laterodorsal position. Another pair of type-3 sensory spots is placed posteriorly in ventrolateral position ( Figs. 10C, G View Fig , 11E View Fig , and 12B View Fig ). Two ventromedial sensory spots are placed anteriorly on the segment, partially hidden by the free flap of segment 10. We could not assign these structures to any specific type of sensory spot, even though they resemble type-6.

On this segment, the teeth of the primary pectinate fringe are shorter and smaller than on segments 1 to 10, and cuticular hairs are absent. The female shows cuticularized gonopores at the anterior margin of the sternal plate, almost at the junction between segments 10 and 11 ( Fig. 9E View Fig ).

3.2.6. Sexual dimorphism

The two males bear a pair of laterodorsal acicular spines on segment 10, ending after the posterior edge of the segment ( Figs.10F View Fig and 12B View Fig ), and a ventromedial gland cell outlet on segment 10. In addition, the males lack gonopores on segment 11, lateroventral acicular spines on segment 10, and ventromedial appendages on segments 5, 6, and 7 ( Fig. 10C, E View Fig ), all of which are present only in the female (see chapter 3.2.5.).

3.2.7. Ecology

C. clarae sp. nov. was found at different sites off Livorno (Ligurian Sea, Tuscany, Central Italy). The bottom depth of the sampling sites ranged from 111 to 113 m. The sediment was made up on average of sandy mud or loamy sand (see Table 1). C. clarae sp. nov. co-occurred with other kinorhynchs, i.e.: P. quadridentatus , Fujuriphyes cf. rugosus (Zelinka 1928) , P. communis , P. giganteus , S. armiger , Echinoderes cf. capitatus , Echinoderes sp. 2 , and Echinoderes sp. 3 (see Dal Zotto & Todaro, 2016). The other meiobenthic taxa associated with C. clarae sp. nov. were mainly nematodes, polychaetes, harpacticoids, tanaidaceans, ostracods, amphipods, cumaceans, gastropods, bivalves, priapulids, and loriciferans.

The densities of C. clarae sp. nov. were of 1 ‾ 2 individuals/ 10 cm 2. Compared to theother associated kinorhynchspecies it was rare, found at four out of twelve investigated sites, and scarce.

3.3. Differential diagnosis

Six species of Condyloderes have been described to date, i. e., C. multispinosus , C. paradoxus Higgins, 1969 , Condyloderes setoensis Adrianov, Murakami & Shirayama, 2002 , C. storchi Higgins, 2004 in Martorelli & Higgins, 2004, Condyloderes kurilensis Adrianov & Maiorova, 2016 , and C. shirleyi . Two additional species are described from off California and the Gulf of Mexico by SØrensen etal. (2019).

C. agnetis sp. nov. and C. clarae sp. nov. can be distinguished from their congeners bythe presence of (1) longitudinal rows of cuticular hairs on segments 1 ‾ 9 and (2) a lateral accessory acicular spine on segment 1 ( Table S2; Neuhaus et al. 2019; this paper).

C. agnetis sp. nov. can be differentiated from all its congeners by (1) a subdorsal cuspidate spine on segment 3, (2) a paradorsal cuspidate spine on segment 7, (3) a sublateral cuspidate spine on segment 7, (4) the lack of a paradorsal type-6 sensory spot on segment 5, and (5) a very short midterminal spine in comparison to the lateral terminal accessory spine ( Table S2; Neuhaus et al. 2019; this paper).

C. clarae sp. nov. can be identified from all its congeners by (1) the lack of a paradorsal type-6 sensory spot on segments 1 and 4, (2) the lack of a sublateral type-6 sensory spot on segments 3 and 6, (3) the lack of a ventromedial type-6 sensory spot on segment 8, (4) the existence of a ventromedial female-specific appendage on segment 5, and (5) the lack of a ventromedial female-specific appendage on segment 8 ( Table S2; Neuhaus et al. 2019; this paper).

C. agnetis sp. nov. can be distinguished from C. clarae sp. nov. by (1) a larger trunk length (302 ‾ 327 M m versus 215 ‾ 229 M m length), (2) a shorter midterminal spine (18 ‾ 30 M m versus ca. 55 M m length; see Tables 4 and 5 for average values, MTS/TL, and MTS/LTAS of both species), (3) the existence of a lateral accessory cuspidate spine on segment 2 versus its lack, (4) the existence of a subdorsal cuspidate spine on segment 3 versus its lack, (5) the existence of paradorsal and sublateral cuspidate spines on segment 7 (but spines may be missing naturally) in C. agnetis sp. nov. versus their lack in C. clarae sp. nov., (6) the existence of a paradorsal type-6 sensory spot on segments 1 and 4 versus its lack on these segments, (7) the existence of a ventromedial type-6 sensory spot on segments 3, 8, and 11 versus its lack on these segments, (8) the existence of a sublateral type-6 sensory spot on segments 3 and 6 versus its lack on these segments, (9) the existence of a laterodorsal type-6 sensory spot on segments 3 (but may be missing naturally), 6, and 11 versus its lack on these segments, and (10) the existence of a ventromedial female-specific appendage on segments 6 ‾ 8 versus its existence on segments 5 ‾ 7 ( Table S2). Additional, though weaker, traits distinguishing C. agnetis sp. nov. from C. clarae sp. nov. are (1) shorter and less robust cuticular hairs as well as fewer hairs in each longitudinal row (3 ‾ 5 versus 6 hairs per row) and more rows of hairs both on the sternal plates (9 versus 6 ‾ 7 rows) and tergal plates (40 ‾ 44 versus 24 ‾ 26 rows), (2) the lack of rows of cuticular hairs on segment 10 versus their presence in C. clarae sp. nov.