Pholeterides furtiva Illg, 1958

Boxshall, Geoff A. & Marchenkov, Andrey, 2007, A revision of the Brementia - group of genera (Copepoda: Notodelphyidae), with descriptions of a new genus and four new species, Zootaxa 1459, pp. 37-68 : 63-65

Pholeterides furtiva Illg, 1958

Material examined: Paratype females ( USNM 92606 and 92606a).

Supplementary Description: Illg (1958) provided a full description of the body form and swimming legs of this species. Here we add some details concerning the cephalosomal appendages and caudal rami. Illg (1958: Figure 19a, d) illustrated a claw-like structure (Fig. 13A) with strongly sclerotised tip located on the side of the cephalosome but did not mention it in the text. We interpret this as representing the posterolateral angle of dorsal cephalic shield. The caudal rami (Fig. 13B) are well developed with each ramus bearing a strongly sclerotised claw which carries a small barb on the margin near the tip.

The antenna is 2-segmented. Illg (1958: Figure 19h) described the claw of the antenna as bearing “two reduced setae … inserted at about equal intervals on one of the margins”. The paratype material (Fig. 13C) shows the sclerotised curved claw at the tip, with 2 sclerotised triangular plates located near the base of the claw. Adjacent to these are numerous surface elements. We consider it not possible to identify these elements as either true setae or enlarged surface setules from the ornamentation covering the surface of this species. We are unable to accept Illg’s interpretation of some of these elements as setae.

The 3 pairs of reduced and transformed mouthparts correspond in general with Illg’s description. The only differences are in details of ornamentation. The first limb (Fig. 13D) is represented by a simple tapering lobe, with a wide base armed with 2 setae terminally and 3 setae basally. This appendage is probably the mandible, represented only by the palp. The second limb (Fig. 13E–F) is indistinctly 3-segmented and bilobed. The basal segment is unarmed. The second segment bears 1 inner seta, 1 outer seta and medial and lateral lobes: medial lobe elongate with 1 long and 1 short seta inserted terminally; lateral lobe smaller and armed with 3 terminal setae. This is probably the maxillule. The third limb (Fig. 13G–H) is indistinctly 4-segmented and ornamented with setules, so distinguishing between true setal elements and ornamentation is problematic. The first segment is large and probably armed with 2 setae near inner distal angle; second segment short with stout lateral seta; third segment armed with 1 elongate seta and 1–2 short elements; distal segment with 2 long and 1 short terminal setae. This is probably the maxilla.

FIGURE 13. Pholeterides furtiva Illg, 1958 paratype female ( USNM 92606 and 92606a). A, Sclerotised angular process representing posterolateral corner of dorsal cephalic shield; B, Caudal ramus; C, Distal part of antenna, with claw and adjacent sclerotised areas stippled; D, First oral appendage; E, Second oral appendage on left side; F, Second oral appendage on right side; G, Third oral appendage on left side; H, Third oral appendage on right side. Scale bars: A–B = 50 μm, C–H = 25 μm.

Remarks: Illg (1958) was unable to determine the homology of the three pairs of retained mouthparts. We consider it likely that they represent the mandibles to maxillae, with the maxillipeds lacking, but confirmation of this must await the discovery of copepodid stages or males.