Caprella novaezealandiae Kirk, 1878

Caprella novaezealandiae Kirk, 1878

( Figs. 1–2 View FIGURE 1 View FIGURE 2 , 6–8 View FIGURE 6 View FIGURE 7 View FIGURE 8 , Appendix 1)

Caprella novae-zealandiae Kirk, 1878a: 465–466 .— Kirk, 1878 b: 393–394.— McCain, 1969: 286–287.— Thomson, 1879: 330.

[?l Caprella novae-zealandiae . — Mayer, 1882: 71–72; 1890: 76.

Caprella equilibra .—Thomson & Chilton, 1879: 330.

Type material. Neotype: NIWA 155308 View Materials , male (13 mm), Breaker Bay , Wellington, Cook Strait, New Zealand, 41°19.8’S, 174°49.932’E, 0 m, Z15829, on Macrocystis sp. , coll. A-N. Lörz & M. Thiel, 30/01/2013. GoogleMaps

Type locality. Breaker Bay , Wellington, Cook Strait, New Zealand, 41°19.8’S, 174°49.932’E GoogleMaps .

Other material examined. NIWA 114870 View Materials , 1 female (9 mm; drawn and dissected), Breaker Bay , Wellington, Cook Strait, New Zealand, 41°19.8’S, 174°49.932’E, 0 m, Z15829, on Macrocystis sp. , A-N. Lörz & M. Thiel, 30/01/2013 GoogleMaps ; NIWA 155309 View Materials , 1 male (6 mm), Breaker Bay , Wellington, Cook Strait, New Zealand, 41°19.8’S, 174°49.932’E, 0 m, Z15828, on Macrocystis sp. , coll. A-N. Lörz & M. Thiel, 01/02/2013 GoogleMaps ; NIWA 155310 View Materials , 1 male (7 mm), Breaker Bay , Wellington, Cook Strait, New Zealand, 41°19.8’S, 174°49.932’E, 0 m, Z15829, on Macrocystis sp. , coll. A-N. Lörz & M. Thiel, 30/01/2013 GoogleMaps ; NIWA 155311 View Materials , 1 female (7 mm), Breaker Bay , Wellington, Cook Strait, New Zealand, 41°19.8’S 174°49.932’E, 0 m, Z15829, on Macrocystis sp. , coll. A-N. Lörz & M. Thiel, 30/01/2013 GoogleMaps ; NIWA 155321 View Materials , 2 females (6–7 mm), 2 males (8 mm), Breaker Bay , Wellington, Cook Strait, New Zealand, 41°19.8’S, 174°49.932’E, 0 m, Z15828, on Macrocystis sp. , coll. A-N. Lörz & M. Thiel, 01/02/2013 GoogleMaps ; NIWA 155322 View Materials , 1 female (6 mm), Breaker Bay , Wellington, Cook Strait, New Zealand, 41°19.8’S, 174°49.932’E, 0 m, Z15829, on Macrocystis sp. , coll. A-N. Lörz & M. Thiel, 30/01/2013 GoogleMaps ; NIWA 155323 View Materials , 1 female (8 mm), 1 juvenile (4 mm), Breaker Bay , Wellington, Cook Strait, New Zealand, 41°19.8’S, 174°49.932’E, 0 m, Z15829, on Macrocystis sp. , coll. A-N. Lörz & M. Thiel, 30/01/2013 GoogleMaps ; NIWA 155324 View Materials , 1 female (7 mm), Breaker Bay , Wellington, Cook Strait, New Zealand, 41°19.8’S, 174°49.932’E, 0 m, Z15829, on Macrocystis sp. , coll. A-N. Lörz & M. Thiel, 30/01/2013 GoogleMaps .

Diagnosis. Head with subacute triangular projection, directed forward; body otherwise smooth and robust, pereonite 4 with small distal hump. Antenna 1 shorter than ½ of body; peduncle articles 1–2 slender in male and female, sparsely setose, longer than flagellum. Antenna 2 longer than peduncle of antenna 1, bearing long dense setae on ventral margin. Mandible without palp. Gnathopod 1 robust, with palmar margin of propodus setose with pair of proximal grasping spines; palm straight; dactylus serrate. Gnathopod 2 in male arising at midlength of pereonite 2; basis longer than ½ length of propodus (0.65 ×) and less than ½ of pereonite 2 (0.38 ×); palmar region of propodus concave, weakly setose with distal rectangular projection/shelf and prominent long proximal spiniform defining tooth; dactylus strong, apex acute and constricted medially with inner margin serrate. Gnathopod 2 in female inserted distally on pereonite 2; palm of propodus straight. Gills rounded and quite large and inflated in male, maximum diameter ½ of length to pereonite 4. Gills oval to elliptical and smaller in female. Pereopods 3 and 4 absent. Pereopods 5–7 similar in length posteriorly; palmar margin of propodus straight bearing short robust and simple setae with two median toothed grasping spines.

Description of neotype. (Male, 13 mm, NIWA 155308). Body: head anterodistal margin produced to form an anteriorly directed tooth. Head fused with pereonite 1, suture present and visible. Pereonite smooth, no dorsal projections; pereonite 4 with rounded distal hump. Ratio of lengths pereonites 1 (not including head) 1: 3.4: 3.25: 3.25: 2.2: 1.7: 1.2.

Head: Antenna 1 0.37 × body; peduncular article 2 the longest, 1.2 × article 1, 1.7 × article 3; flagellum 0.7 × peduncular length with 13 articles. Antenna 2 0.8 × antenna 1 length; peduncular article 4 subequal in length to article 5 (1.1 ×). Mouthparts: lower lip inner plate rounded. Mandible right incisor with five teeth, lacinia mobilis with seven teeth followed by three plumose setae, molar distinct. Mandible left incisor with five teeth, lacinia mobilis with three toothed teeth followed by two plumose setae, molar distinct. Maxilla 1 outer plate with seven apical tooth-like robust setae; palp two-articulate; article 2 longer than article 1 (3.5 ×) with six apical robust setae and single line of five medial slender setae. Maxilla 2 inner plate, oval, with 12 marginal and apical slender setae; outer plate with nine mainly apical slender setae, inner plate shorter than outer plate. Maxilliped inner plate with two stout setae on distal margin, with line of setae on entire distal margin and along distal half of inner margin; outer plate 1.5 × inner plate with four robust setae on inner margin, slender setae apically; palp four-articulate, article 2 longest, setose along entire inner margin; dactylus inserted apically, no setose lobe/hood apically, fine hair-like setae along length medially, slight serration at tip.

Gnathopod 1 basis subequal to ischium, merus, carpus combined, posterodistal lobe absent; merus produced to form subacute, setose posterior lobe; carpus subtriangular, densely setose on posterior lobe, posterior lobe broadly rounded extended in line with merus lobe; propodus subtriangular to subrectangular, length 1.7 × width, setae not along anterior margin; palm beginning ¼ distance along posterior margin; proximal defining corner equipped with pair of smooth robust setae (grasping spines) followed by ca. 25 setae along palm, palm slightly serrated; dactylus weakly curved, inner margin rounded serrated, small setae along both inner and outer margins, slightly bifid tip. Gnathopod 2 basis anterior margin smooth, medial surface covered in small protuberances, basis slightly produced to form small triangular flange; ischium 0.15 × basis, without anterior distal triangular lobe; propodus longer than wide (length 1.9 × width); anterior margin with protuberances and small setae and on long seta; palm beginning ⅓ distance along posterior margin, proximal defining tooth long without robust setae, apically grinding surface and one slender seta; palm with predactylar rectangular shelf/projection, row of small setae along palm; dactylus outer margin proximal ⅓ with small setae, inner margin serrated. Gill 3 length 0.67 × pereonite 3; gill 4 subequal to gill 3. Pereopod 5 basis 0.55 × propodus, posterior margin smooth and expanded distally to form subacute flange; ischium 0.6 × basis; merus 0.25 × basis; carpus 0.64 × basis, anterior margin lined with slender setae, posterior margin produced to form subacute setose lobe; propodus longest, with paired combed robust setae 0.25 along posterior margin on rounded corner, palm straight lined with 2 robust and 12 slender setae; propodus posterior margin lined with occasional setae; propodus length 2.1 × width; dactylus long reaching to defining corner, curved, inner margin smooth but with fringe of small setae, outer margin with occasional setae. Pereopod 6 subequal in length to pereopod 5, similar structure to P5; length propodus 2.1 × width; dactylus inner margin with grinding surface. Pereopod 7 similar to pereopods 5 and 6; propodus posterior margin lined with slender setae; length propodus 2.3 × width.

Variations/ sexual dimorphism. Mature female, NIWA 114870, 9 mm. Ratio of pereonites 1–7 (not including head) 1: 4.5: 4.5: 3.5: 3.0: 2.2: 1.5. Antennae 1 slightly shorter than ½ body. Antenna 1 slender; peduncle article 2 longest, 1.2 × article 1, 1.7 × article 3; articles 1 longer than article 3 (1.4 ×); flagellum nine articles, flagellum subequal to peduncle.Antenna 2 reaching past the peduncle of antenna 1, and to halfway along flagellum. Gnathopod 1 basis subequal—slightly longer than ischium, merus, carpus combined (1.1 ×); carpus subtriangular, setose on broadly rounded posterior lobe; propodus subtriangular, length 1.8 × width, without setae along anterior margin; palm beginning ⅕ along posterior margin; proximal defining corner equipped with pair of smooth robust setae followed by ca. 22 setae along slightly serrate palm; dactylus weakly curved, serrate inner margin. Gnathopod 2 basis anterior margin smooth, slightly produced to form small triangular flange; ischium 0.15 × basis, without lobe; propodus longer than wide (length 2.1 × width); palm beginning ¼ along posterior margin, proximal defining corner with two smooth robust setae; palm setose and smooth, with two small rounded teeth/projections situated on distal ¼ of palm, dactylus inner margin distally serrate and lined with small setae, outer margin with small setae.

Distribution. Wellington, Cook Strait, New Zealand

New Zealand biosecurity status. Native.

Genbank Accession numbers: SUB14807890 M08Cnzelandiae COI PQ522032; SUB14807870 M08_ Cnzelandiae_nSSU PQ521244.

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Remarks. We remove Caprella novaezealandiae from synonymy with Caprella penantis Leach, 1814 (placed in synonymy by McCain 1968) and establish NIWA 155308 as the neotype for Caprella novaezealandiae Kirk, 1878 . No type specimens were formally assigned and there is no evidence of any extant original material of Kirk’s. The neotype is from the original type locality (Wellington, Cook Strait, New Zealand) and fits as closely as possible to the original description. The original description documented a caprellid of approximately 25 mm with a forward directed tooth on the head; first pereonite short, second longest and then subsequent pereonites decreasing in length; antennae 1 ⅖ of body; antennae 1 flagellum articles distal corners produced without setae, antenna 2 reaching to the end of antenna 1 peduncular article 2; gnathopod 2 attached in the distal ½ of pereonite 2, propodus ovate, palm with prominent posterior tooth and a smaller but distinct anterior tooth (not a lobe), dactylus strongly curved; pereopods 5–7 with concave palm with posterodistal defining tooth.

Caprella novaezealandiae as described here differs from the original description by the articles of antenna 1 flagellum, which, while also being produced, bear small setae, and antenna 2 is longer in proportion to antenna 1, reaching past the peduncle. These differences could be related to size. The longest specimen (neotype) examined was a male of 13 mm, notably shorter than the inch-long specimen documented in Kirk (1878).

Caprella novaezealandiae and C. serenae sp. nov. are part of the complex of species morphologically similar to Caprella penantis Leach, 1814 . In the original description, Kirk mentions that C. novaezealandiae has similarities to C. geometrica and both species were placed in synonymy with C. penantis by McCain (1968), moving it from synonymy with C. equilibra (placed there by Thomson & Chilton 1885, 1886). However, in his treatise on New Zealand caprellids, McCain (1969: 286) also treats C. novaezealandiae as unrecognisable and that “ Caprella novaezealandiae as having an anteriorly directed triangular tooth on the cephalon” and mentions that it is close to Caprella geometrica , a member of the Caprella acutifrons-penantis complex. “Perhaps Caprella novae-zealandiae is indeed a member of this complex since its species occur throughout the world. If so, Kirk’s name would have priority over any of Mayer’s varietal names (1882, 1890) and should possibly replace one or other of the names now in use for Pacific forms of this complex. I have no material of this species …” ( McCain 1969: 286–287).

Caprella penantis was originally considered a cosmopolitan species. However, recent studies have shown, like so many other seemingly ‘cosmopolitan’ species, that it is a complex of closely related, morphological similar (but not indistinguishable) species ( Cabezas et al. 2013b; Sánchez-Moyano et al. 2014, Cabezas et al. 2022). Both C. novaezealandiae and C. serenae sp. nov. belong in the ‘ penantis’ complex of species. The analysis by Cabezas et al. (2022) indicated that there were three main lineages of Caprella penantis sensu stricto. As there are a number of forms of C. penantis around the world, it is very difficult compare all the forms together. Therefore the New Zealand species and those on an opposite side of the Pacific Ocean (anecdotally there are strong similarities between New Zealand’s marine fauna and that on the south-eastern side of the Pacific Ocean) were compared ( Table 2). Despite possessing similarities, such as the presence of an acute/subacute projection on the head and the shape of gnathopod 2 propodus (short and robust with one dominant tooth), there are distinct morphological differences separating both these New Zealand species from the ‘ penantis’ species group ( Table 2).

With the diversity of C. penantis -like forms in New Zealand as shown in this paper, it is reasonable to assume that C. penantis does not occur (as yet) in New Zealand waters. This seems to be corroborated by the molecular evidence provided ( Fig. 2 View FIGURE 2 , Appendix 1). The COI sequence analysis supports these distinctions ( Fig. 2 View FIGURE 2 ) with C. novaezealandiae differing from C. serenae by 74 substitutions, consistent with being a distinct species. These sequences differed significantly from the other species in the analysis and even differed significantly from C. penantis and C. andreae despite the obvious morphological similarities.