Condyloderes Higgins 1969

Condyloderes sp. 1

(Fig. 32; Tables 1, 7)

Material examined. One recently moulted male (USNM 1209806) mounted for light microscopy and previously identified as a juvenile stage of Condyloderes paradoxus from the Bay of Bengal, India (Fig. 1; Table 1).

Description. For some basic measurements see Table 7.

Trunk. The trunk is divided into 11 segments. Whereas the cuticle of the first trunk segment is ring-like without any articulation, the cuticle of segments 2–10 possesses both a midventral and a lateral articulation resulting in a tergal and two sternal plates (Fig. 32A). In segment 11, a single sternal and tergal plate exist although the sternal plate reveals a paraventral fold on both sides (Fig. 32A).

The anterior margin of the first trunk segment is smooth (Fig. 32A). The trunk cuticle and the pachycyclus are only very weakly developed (Fig. 32A). At the posterior end of all segments, the free flap overlapping the subsequent segment terminates in a primary pectinate fringe. The free flap is missing where the spines originate.

Surface characters of the cuticle like hairs were not recognizable. Also, type-6 sensory spots were extremely difficult to trace if at all because of the thin cuticle. Type-3 sensory spots occur ventrolaterally next to the lateral terminal accessory spine and subdorsally on segment 11.

Segments 1–10 bear a middorsal, segments 1–9 on each side a lateroventral spine, segment 10 also possesses a subdorsal to laterodorsal spine, and segment 11 has a spine in a lateral accessory position (= lateral terminal accessory spine) and as the midterminal spine (Fig. 32A, C; Table 7); the spines are hirsute and acicular. A short hirsute cuspidate spine with a basally thickened and an apically thinner part appears ventrolaterally on segment 5 but displaced towards the ventromedial position (Fig. 32A), in a lateral accessory position on segment 8, as well as sublaterally on segments 3, possibly 4 and 9 (Fig. 32A; Table 7).

Gonads are well developed and extend until the middle of the trunk revealing sperm in the posterior segments (Fig. 32B).

Comparison with previous description. Opposite to Higgins (1969) who identified the single specimen as a juvenile of Condyloderes paradoxus, we regard the specimen as a recently moulted male of a new species. The specimen reveals a thin cuticle typical for a juvenile or a recently moulted adult, a free flap only occurring in adults but not in juveniles, and a well developed gonad with sperm characteristic of a male. The specimen is assumed to belong to a new species, because it lacks the cuspidate spine ventrolaterally on segments 2 and 9 and in a lateral accessory position on segment 4, whereas C. paradoxus possesses a cuspidate spine in these positions. In addition, the specimen reveals a sublateral cuspidate on segments 3, possibly 4 and 9 lacking in C. paradoxus, and the ventrolateral cuspidate spine on segment 5 is displaced towards the ventromedial position in comparison with C. paradoxus. Sublateral cuspidate spines do not occur in any other known species of Condyloderes (Table 7; Higgins 1969; Adrianov et al. 2002; Martorelli & Higgins 2004; Sørensen et al. 2010b; Adrianov & Maiorova 2016). The specimen is not described formally as a new species, because only a single specimen is available, many cuticular characters are hard to recognize if at all also because of the thin cuticle, the specimen is covered with detritus hampering observation, and the preparation is not too satisfying.