Waematau rereke, Ball & Webber & Shepherd, 2017

Ball, P., Webber, W. Richard & Shepherd, Lara D., 2017, New species and phylogeny of landhoppers in the genus Waematau Duncan, 1994 (Crustacea: Amphipoda: Talitridae) from northern New Zealand, Zootaxa 4306 (2), pp. 151-207 : 181-185

Waematau rereke sp. nov.

( FigS 21–23 )

Type material. Holotype: female (MNZ CR.023854), body length 9.0 mm, Unuwhao (A), Northland, New Zealand, broadleaf foreSt, pit trap, coll. Ball O.J. -P., 12 Feb 2007 . Allotype: male (MNZ CR.023855), body length 9.0 mm, Unuwhao (A), Northland, New Zealand, broadleaf foreSt, pit trap, coll. Ball O.J. -P., 12 Feb 2007 . ParatypeS: 1 female (MNZ CR.023856), Unuwhao (A); 1 female (MNZ CR.023857), Unuwhao (A).

Diagnosis. Medium Sized (body length 8–10 mm), weakly Sexually dimorphic. Eye Small, approximately one quarter head length. Antenna 2 aS long aS head and firSt 2–3 pereoniteS. Maxilliped outer plate not arcuate or diStally acute. Gnathopod 1 propoduS SubSimple in both SexeS; gnathopod 2 propoduS mitten-Shaped in both SexeS. Gill on pereopod 6 extending aS a long, Slender proceSS poSteroventrally with no Subapical lobe. PleopodS 1 and 2 well developed, biramouS; pleopod 3 veStigial, rami abSent, peduncle reduced. Uropod 1 diStolateral robuSt Seta up to 0.3 timeS length of outer ramuS; outer ramuS with no dorSal robuSt Setae, inner ramuS with dorSal robuSt Setae. Uropod 2 rami with dorSal robuSt Setae. Uropod 3 peduncle with Single robuSt Seta; ramuS approximately 0.5 timeS length of peduncle with 2 robuSt Setae. TelSon marginS and apex with robuSt Setae.

Description. AdultS ( Fig. 21 ) 8–10 mm long. Head Slightly longer than pereonite 1. Eye Small, approximately one quarter head length.

Antenna 1 ( Fig. 21 ) juSt reaching peduncle article 5 of antenna 2; articleS 2 and 3 of peduncle Subequal in length, article 3 narrower; flagellum with 3–4 articleS, penultimate article geniculate. Antenna 2 ( Fig. 21 ) aS long aS head and firSt 2–3 pereoniteS; article 5 of peduncle 1.2–1.3 timeS longer than article 4; flagellum 1.2–1.3 timeS longer than peduncle, conSiSting of 12–16 Short articleS.

Upper lip broadly rounded and SetoSe apically. Mandible left lacinia mobiliS 4-dentate. Lower lip inner lobeS well developed, SetoSe. Maxilla 1 inner plate Slender, tapering diStally, with two apical plumoSe Setae; outer plate broad with 9 apical Serrate robuSt Setae, outer margin with veStigial palp. Maxilla 2 inner plate Slightly Shorter than outer plate, apex with many curved robuSt Setae, plumoSe Seta on inner margin; outer plate apex with many curved robuSt Setae. Maxilliped outer plate broad, not arcuate or diStally acute; palp article 2 with Small diStomedial lobe, article 4 preSent but much reduced and button-like.

Gnathopod 1 ( FigS 21 , 22 ) Similar in both SexeS. Coxa deeper than wide, ventral margin with few robuSt Setae; baSiS narrowing proximally; iSchium Short; meruS poSterior margin not produced into a lobe; carpuS narrow, poSterior margin produced into a very Small, moderately SetoSe lobe; propoduS narrow, Subrectangular, approximately 0.6 timeS length of carpuS with no diStinct lobe, palm very Short and indiStinct; SubSimple.

Gnathopod 2 ( FigS 21 , 22 ) Similar in both SexeS. Coxa aS wide aS deep, ventral margin convex, ventral and poSteroventral marginS with Small robuSt Setae, poSterior margin with Subacute proceSS; baSiS narrowing proximally; iSchium narrow; meruS Subequal in length to iSchium, produced poSterodiStally into lobe covered in palmate Setae; carpuS elongate with lobe covered in palmate Setae poSterodiStally; propoduS mitten-Shaped, approximately 0.9 timeS length of carpuS, broadening diStally, lobe apically rounded and broad; dactyluS Short.

Pereopod 3 coxa wider than deep, anterodiStal corner rounded, ventral margin weakly convex with few robuSt Setae, poSterodiStal corner curving to form Subacute proceSS; baSiS narrowing proximally; iSchium Short; meruS narrowing proximally; carpuS 0.6–0.7 timeS length of meruS; propoduS approximately 1.3 timeS longer than carpuS, weakly narrowing diStally.

Pereopod 4 coxa wider than deep, ventral margin nearly Straight with few robuSt Setae, poSterodiStal corner curving to form Subacute proceSS; baSiS broadening diStally; iSchium Short; meruS broadening diStally; carpuS 0.7– 0.8 timeS length of meruS; propoduS approximately 1.2 timeS longer than carpuS, weakly narrowing diStally; dactyluS poSterior margin weakly pinched.

Pereopod 5 coxa ventrally bilobate; baSiS Subovate; iSchium Short; meruS Strongly broadening diStally with large terminal robuSt Setae; carpuS Subequal in length to meruS; propoduS approximately 1.3 timeS longer than carpuS.

Pereopod 6 coxa ventral margin with few tiny robuSt Setae; baSiS Subovate to elliptic; iSchium Short; meruS broadening diStally; carpuS Slightly Shorter than meruS, weakly broadening diStally; propoduS approximately 1.3 timeS longer than carpuS, Slender.

Pereopod 7 Slightly longer than pereopod 6 (note: pereopod 7 on left Side regenerating in holotype); coxa wider than deep, ventral margin convex with few tiny robuSt Setae; baSiS broadly Subovate; iSchium Short; meruS narrowing proximally; carpuS Subequal to meruS, weakly broadening diStally; propoduS approximately 1.4 timeS longer than carpuS.

Oostegites preSent on gnathopod 2 and pereopodS 3–5, weakly SetoSe diStally (with 5–9 Setae). OoStegite on gnathopod 2 moderately elongate, anterior margin with concave excavation, broadeSt proximally. OoStegiteS on pereopodS 3 and 4 elongate, anterior marginS concave, weakly expanded diStally. OoStegite on pereopod 5 narrowing diStally.

Gills ( Fig. 22 ) preSent on gnathopod 2 and pereopodS 3–6. Gill on gnathopod 2 broad, convoluted, and diStally lobed. Gill on pereopod 3 Simple, elongate, broader proximally, narrowing diStally. Gill on pereopod 4 moderately elongate, proximally convoluted. Gill on pereopod 5 proximally convoluted, diStinct lobe preSent diStally. Gill on pereopod 6 largeSt, convoluted and expanded proximally with Small lobe near baSe, long, Slender, rounded to weakly elbowed or angular proceSS with Subacute tip extendS poSteroventrally.

Pleopods 1–2 ( Fig. 23 ) well developed, biramouS, pleopod 2 Subequal to or Slightly Shorter than pleopod 1; peduncle without long marginal Setae; inner ramuS approximately 0.3 timeS longer than outer ramuS, longeSt ramuS on each pleopod approximately 0.7 timeS length of peduncle. Pleopod 3 ( Fig. 23 ) veStigial; peduncle reduced, approximately 5 timeS longer than wide at baSe; rami abSent.

Epimeron 1 Shallower than epimera 2–3, anteroventral margin convex, poSteroventral corner with Small Subacute proceSS, poSterior margin with SparSe minute SerrationS and tiny Setae. Epimeron 2 deepeSt, poSteroventral corner with Small Subacute proceSS, poSterior margin with minute SerrationS and tiny Setae. Epimeron 3 ( Fig. 23 ) anteroventral corner rounded, poSteroventral corner with Small Subacute proceSS, poSterior margin weakly Sinuate with minute SerrationS and tiny Setae.

Uropods 1–3 not Sexually dimorphic. Uropod 1 ( Fig. 23 ) peduncle lateral margin with 2 large dorSal robuSt Setae, meSial margin with 2 medium to large dorSal robuSt Setae either Side of the midpoint and a large Subapical robuSt Seta, diStolateral robuSt Seta 0.25–0.3 timeS length of outer ramuS; rami approximately 0.7 timeS length of peduncle with long and Short Subapical and apical Stout robuSt Setae, outer ramuS without dorSal robuSt Setae, inner ramuS with 3 dorSal robuSt Setae.

Uropod 2 ( Fig. 23 ) peduncle approximately 0.5 timeS length of uropod 1 peduncle, weakly narrowing diStally, lateral margin with 2 dorSal robuSt Setae increaSing in Size diStally and 1 Subapical robuSt Seta, meSial margin with 1 medium Subapical robuSt Seta; rami Subequal in length to peduncle with long and Short Subapical and apical Stout robuSt Setae, outer ramuS with 3 dorSal robuSt Setae increaSing in Size diStally, inner ramuS with 2 dorSal robuSt Setae increaSing in Size diStally.

Uropod 3 ( Fig. 23 ) peduncle with 1 long lateral robuSt Seta; ramuS Short, approximately 0.5 timeS length of peduncle, with 1 medium Subapical robuSt Seta and 1 Small apical robuSt Seta.

Telson ( Fig. 23 ) Slightly longer than wide, apically very weakly inciSed, ventral longitudinal furrow preSent, 1– 2 Short robuSt Setae apically and 2–4 medium to long marginal or Submarginal robuSt Setae in angled pairS dorSally and dorSolaterally on each Side.

Etymology. The Specific name iS derived from the Te Reo Maori word for ‘different’ or ‘unuSual’ and referS to the fact that W. rereke waS initially conSidered an unuSual variant of W. reinga .

Habitat. Native foreSt.

Distribution. North ISland, Northland: Unuwhao.

Remarks. Morphologically, W. rereke iS very Similar to W. kohuroa and W. reinga . In all three SpecieS, the penultimate article of antenna 1 iS geniculate, and pleopodS 1 and 2 are well developed and biramouS whereaS pleopod 3 iS veStigial. AlSo, the general Shape and Setation of the telSon and uropodS are Similar, aS are gillS 2–5. Furthermore, all three SpecieS are weakly Sexually dimorphic. With the exception of the veStigial third pleopod and the morphology and Setation of the telSon, W. rereke alSo ShareS theSe traitS with W. ringanohinohi . Key morphological differenceS between all four SpecieS are outlined in Table 3.

Figures

FIGURE 21. Waematau rereke sp. nov., holotype female MNZ CR. 023854 (anterior half, gnathopods 1 – 2), UnuWhao (A), Northland.

FIGURE 22. Waematau rereke sp. nov., allotype male MNZ CR. 023855 (gnathopods 1 – 2, gill 6), UnuWhao (A), Northland.

FIGURE 23. Waematau rereke sp. nov., allotype male MNZ CR. 023855 (pleopods 1 – 2), UnuWhao (A), Northland; paratype female MNZ CR. 023856 (pleopod 3), UnuWhao (A), Northland; holotype female MNZ CR. 023854 (urosome, uropods 1 – 3, telson), UnuWhao (A), Northland.