Phyllopodopsyllus aegypticus Nicholls, 1944

Björnberg, Tagea & Kihara, Terue C., 2013, On Tetragonicipitidae (Crustacea, Copepoda) from the Channel of São Sebastião, Brazil, with description of their nauplii and two new species of Phyllopodopsyllus, Zootaxa 3718 (6), pp. 501-529 : 525-527

Phyllopodopsyllus aegypticus Nicholls, 1944

( Fig. 19 )

Synonymy. Phyllopodopsyllus gertrudi Kunz, 1983 (fide Karanovic et al. 2001)

Material examined. São Sebastião, Cigarras Beach (23°43’47.36’’S, 45°23’53.16’’W): Ten females and 10 males, 0 3 Mar. 2005, in the intertidal zone; G. Lotufo coll. São Sebastião, Sitio de Calhetas Beach (23°49’51’’S, 45°31’26’’W): Ten females and 10 males; 20 copepodites and 30 nauplii, 0 1 Jan 2009, from rock pool; L. Tomita Simões coll.

Description of naupliar stages NII-NVI. The naupliar stages obtained were NII–VI.

NII ( Figs 19 A–B) 100 µm long. Body round, slightly produced posteriorly, redish-brown coloured, very transparent. Only a small part of posterior region is not covered by dorsal shield as shown in Fig. 19 B. Labrum wide, oval shaped, setulose along posterior margin, arising from near anterior margin between bases of antennules, extending caudally across the ventral surface of the nauplius. Posterior to labrum a ventral butterfly-shaped area, heavily setulose, bears a pair of small setae on each side, of which the outer pair protrude beyond the dorsal shield ( Fig. 19 B). Posteriorly and medially there is an indentation, the anal indentation and suture. Antennule 3- segmented, extending beyond dorsal shield, the first segment bare; the second with one seta, the third bearing 3–4 setae.

Antenna: Coxobasis with two processes medially directed. Exopod 1- or 2-segmented with 3 terminal setae, of which one very long.. Endopod strongly developed, longer than exopod, with a long terminal claw, a small medial seta and a very small seta terminally. The coxal processes bear each 2 confluent pinnate setae directed medially to the labrum. The most anterior seta is terminally pinnate.

Mandible: Coxabasis, rectangular in outline, with a row of setules. Coxa with a digitiform, setulose process difficult to perceive below the geniculate setae. Endopod, not distinctly two-segmented, with three geniculate setae proximally and 2 modified setulose setae forming a scissor-like structure distally. A long row of setules ornaments the basis near the insertion points of the setae. Mandibular exopod with 2 setae, one over-reaching the end of the nauplius and the other shorter.

Maxillule: a small protuberance with a short little spine and a minute setule.

NIII ( Fig. 19 C): Body slightly more elongated. Differs from NII mainly in the length of the posterior terminal setae. The maxillule anlage now shows four terminal setae: one longer and stronger, 2 very thin ones, lateral to the strong one and a minute setule. Two long pointed processes are added (arrowed), one on each side of the ventral wall, between the maxillule and the former butterfly structure. Sometimes the pointed process only appears in later naupliar stages.

NIV ( Fig. 19 D) differs from NIII as follows: 125 µm long, body with 2 terminal setae on each side posteriorly, maxillule bearing thicker setae on outer and inner sides of the main thick seta. Antennule with one seta added to third segment.

NV ( Fig. 19 E) differs from NIV as follows: 159 µm long, body with three terminal setae on each side posteriorly. The pointed process ( Fig. 19 F) of NIII is now shorter and wider proximally.

NVI ( Fig. 19 G) differs from NV as follows: 171 µm long, body with three pairs of anlagen of the next pairs of appendages. The detail of the antenna ( Fig. 19 H) shows the increase in the number of setae and segments on the exopod. The detail of the mandible ( Fig. 19 I) shows pinnate setae, basis and mandibular finger-like process of the appendage.

Remarks. Phyllopodopsyllus aegypticus was described from Ghardaga in the Red Sea and was found again off the Nicobar Is. and South Andaman (Wells & Rao 1987), in Hawaii ( Kunz, 1984 ) and in Costa Rica (Mielke 1992). Its occurrence in Brazilian waters is perhaps another indication that the genera of the Tetragonicipitidae have a tendency to wide distribution, such as already observed for P. setouchiensis .

The naupliar stages of P. aegypticus differ from most of the other tetragonicipitid nauplii occurring in the region by the absence of pointed outer protuberances on the margins of the dorsal shield ( Figs 19 A–C). It is, in general shape, similar to the nauplius of P. setouchiensis .

Figures

FIGURE 19. Phyllopodopsyllus aegypticus Nicholls, 1944 (nauplii). (A) NII and detail of maxillule, ventral; (B) NII, dorsal; (C) NIII and detail of maxillule, ventral; (D) NIV and detail of antennal exopod and maxillule, ventral; (E) NV, latero-ventral; (F) NV right ventral furcal region; (G) NVI, ventral; (H) NVI antenna; (I) NVI mandible. Scale bars: 10 µm.