Re-description of Chevalia aviculae Walker, 1904, five new species and new records of Chevaliidae from Australia and New Zealand (Crustacea: Peracarida: Amphipoda: Senticaudata)

. The amphipod family Chevaliidae Myers & Lowry, 2003 (Amphipoda: Senticaudata) contains two genera: Chevalia Walker, 1904 (13 species), and Bryoconversor Lörz, Myers & Gordon, 2014 (1 species). Chevalia is a marine genus with a cosmopolitan distribution in circumtropical and temperate waters. Prior to this study, records of Chevalia from Australian waters were limited. Here, we describe five new species of Chevalia from Australian waters, C. bardi sp. nov., C. burrewarra sp. nov., C. csiro sp. nov., C. freycinet sp. nov. and C. sprightly sp. nov. The original description of Chevalia aviculae no longer adequately defined the species and is redescribed based on syntypic material from East Cheval Paar, Sri Lanka. Additionally, new distribution records are provided for the New Zealand species Bryoconversor tutus Lörz, Myers & Gordon, 2014. Material reported is from both shallow and deep-water samples from 1–660 m depth. The prevalence of various gender and intersex states within specimens of chevaliids is discussed. An updated key to the 19 world species of Chevaliidae and a field guide to the seven known Australian and New Zealand species is provided.


Introduction
The amphipod family Chevaliidae was established by Myers & Lowry (2003) and included only one genus, Chevalia Walker, 1904, until the recent addition of Bryoconversor Lörz, Myers & Gordon, 2014, from New Zealand waters.Chevaliids have been recorded from depths ranging from 1-1500 m and a variety of habitats including washings from pearl oysters, macroalgae, coarse shelly sand, muddy sand, coral rubble and bryozoans (Lörz et al., 2014).In Chevalia the structure of pereopods 5, 6 and 7, uropods and telson suggest a possible tubiculous habit (Walker, 1904: 290).
The present study aims to clarify the identity of the type species Chevalia aviculae, describe new taxa of Chevalia from Australian waters, provide new records for Bryoconversor tutus from New Zealand and develop an updated key to all species of Chevaliidae.Distribution maps and a field guide to the Australian and New Zealand Chevalia species are provided, together with an updated list of Chevaliid species.

Materials and methods
Samples used in this study were initially fixed in 5% formalin and transferred to 80% ethanol.Material is lodged in the Australian Museum, Sydney (AM), Museums Victoria, Melbourne (NMV), the Western Australian Museum, Perth (WAM) and the Natural History Museum, London (NHMUK).Specimens were dissected in 80% ethanol and slides were made using Aquatex mounting agent.Illustrations were made using Leitz Laborlux K and Wilde Heerbrugg stereomicroscopes fitted with camera lucida.
For this study we were able to access Walker's original type material.Walker names two reefs (paars) as the type locality, East Cheval and Muttuvaratu.As there is only one vial in the collection and multiple original slide preparations, it could be concluded that specimens from both locations were combined.Indeed, during the Pearl Fishery Survey many of the sampling stations represent multiple dredging events combined (Herdman, 1903).Walker did not designate a holotype and the collection is considered syntypic.Owing to the limited state of the original slides, additional wet specimens were dissected and the redescription of C. aviculae is based on a male and 2 female specimens from the syntype series.

Bryoconversor tutus
Lörz, Myers & Gordon, 2014  Bryoconversor tutus Lörz, Myers & Gordon, 2014: 5, figs 3-8.Remarks.The Australian Museum specimens were collected from within 45 km of the type locality.These specimens closely agree with the description of Lörz et al. (2014) except for the striations on the inner rami of uropods 1 and 2 which are absent in these specimens.Also notable is the large difference in body size between the type specimens and the present specimens.The Australian Museum specimens are two males, 8 mm and 5.6 mm in length, whereas the specimens of Lörz et al. (2014) are 1.72 mm (holotype female) and 0.64 mm (paratype male).Lörz et al. (2014) discuss the relationship between the bryozoan host and the amphipods and suggest that the amphipods may exit the bryozoan under certain circumstances and then may recolonise another bryozoan.This suggests that Bryoconversor enjoys a free-living stage outside the bryozoan host and therefore would be able to grow to a larger size without constraints.
Based on characters of gnathopod 2 coxa, basis and propodus, shape of pereopod 7 basis, and telson apical margin, Chevalia aviculae is most similar to C. thomasi.Chevalia aviculae differs from C. thomasi in antenna 1 accessory flagellum is 2-articulate (3-articulate in C. thomasi), and the shape of uropod 3 peduncle, which is broader than long in Chevalia aviculae (longer than broad in C. thomasi).
Etymology.'Bardi' from the regional Aboriginal name for the witchetty grub, in reference to the general impression and size of the species in comparison to other known species of Chevalia; used as a noun in apposition.
Head.Eyes of large size, partially situated in lateral lobe of the head, lateral cephalic lobe rounded.Antennae moderately setose.Antenna 1 length 0.2 times body length; peduncular article 1 longer than article 3; primary flagellum with 9 articles; accessory flagellum 3-articulate, article 1 shorter than article 2, article 3 rudimentary.Antenna 2 slightly shorter than antenna 1; article 4 sub-equal in length to article 5; article 5 length subequal to flagellum; flagellum with 6 articles.Mandible palp article 1 less than 0.4 times article 2, article 2 sub-equal in length to article 3; incisor with 4 teeth, lacinia mobilis with 4 teeth, accessory setal row with 3 setae, molar triturative.Lower lip, inner lobes and outer lobes separated, inner lobes large and fleshy.Maxilla 1 inner plate with marginal setae; outer plate with 9 robust setae; palp 2-articulated with 6 apical robust setae and 4 subapical setae.Maxilla 2 inner plate shorter than outer plate, with oblique facial row of plumose setae on outer margin; outer plate with a row of apical plumose setae.Maxilliped inner plate subrectangular, apical margin with 4 robust setae and several plumose setae, medial margin lined with many plumose setae; outer plate sub-equal in length to palp article 2, with 7 robust setae and row of plumose setae on medial and facial margins, with 3 apical plumose setae; palp, article 2 longer than articles 3 and 4 combined, article 4 with 1 long distal seta.
Remarks.The combination of the simple palm with broad dactylus in gnathopod 1 and the transverse palm of gnathopod 2 separate Chevalia burrewarra sp.nov.from the other Chevalia.The gnathopod 1 of Chevalia burrewarra sp.nov. is distally broad giving a falcate appearance while other species the dactylus is more typically recurved and narrowing distally.Chevalia burrewarra sp.nov.has an extremely long basis on pereopod 4. the length being more than 4 times breadth (other species are about twice
Etymology.Named for the Commonwealth Scientific and Industrial Research Organisation (Fisheries Division) (CSIRO) for their donations of amphipod collections over many years.
Head.Eyes of large size, partially situated in lateral lobe of the head, lateral cephalic lobe subacute.Antennae densely setose.Antenna 1 length 0.52 times body length; peduncular article 1 longer than article 3; primary flagellum with 11 articles; accessory flagellum 3-articulate, article 1 shorter than article 2, article 3 rudimentary.Antenna 2 slightly shorter than antenna 1; article 4 length 1.1 times article 5; article 5 length 0.8 times flagellum; flagellum with 8 articles.Mandible palp, article 1 length 0.2 times article 2, article 2 sub-equal in length to article 3; incisor with 4 teeth, lacinia mobilis with 2 teeth, accessory setal row with 3 setae, molar triturative.Lower lip, inner lobes and outer lobes separated, inner lobes large and fleshy.Maxilla 1 inner plate with a few marginal setae; outer plate with 9 robust setae; palp 2-articulated with 5 apical robust setae and 1 slender subapical seta.Maxilla 2 inner plate shorter than outer plate, with oblique facial row of plumose setae on outer margin; outer plate with a row of apical plumose setae.Maxilliped inner plate subrectangular, apical margin with 3 robust setae and several plumose setae, medial margin lined with many plumose setae; outer plate shorter than palp article 2, with 7 robust setae and row of plumose setae on medial and facial margins, with 2 apical plumose setae; palp, article 2 longer than articles 3 and 4 combined, article 4 with 1 long distal seta.
Remarks.Chevalia csiro sp.nov.and C. freycinet sp.nov.have the bases of pereopods 5 to 7 rectangular while other species have more ovate bases.In C. csiro sp.nov. the gnathopod 2 palm excavation is more pronounced with a distal shelf present where in C. freycinet sp.nov. the shelf is absent, and the palmar excavation is poorly developed.
Etymology.Named from the type locality as a noun in apposition.
Head.Eyes of small size, situated away from lateral cephalic lobe, lateral cephalic lobe subacute.Antennae densely setose.Antenna 1 subequal to body length; peduncular article 1 longer than article 3; primary flagellum with 9 articles; accessory flagellum 3-articulate, article 1 shorter than article 2, article 3 rudimentary.Antenna 2 length 0.7 times length antenna 1; article 4 length subequal article 5; article 5 length 0.9 times flagellum; flagellum with 7 articles.Mandible palp, article 1 length 0.2 times article 2, article 2 length 1.1 times article 3; incisor with 4 teeth, lacinia mobilis with teeth, accessory setal row present, molar triturative.Lower lip, inner lobes and outer lobes separated, inner lobes large and fleshy.Maxilla 1 inner plate with a few marginal setae; outer plate with 10 robust setae; palp 2-articulated with 4 apical robust setae and 2 subapical setae.Maxilla 2 inner plate shorter than outer plate, with oblique facial row of plumose setae on outer margin; outer plate with a row of apical plumose setae.Maxilliped inner plate subrectangular, apical margin with 4 robust setae and several plumose setae, medial margin with several plumose setae; outer plate shorter than palp article 2, with 3 robust setae and few plumose setae on medial and facial margins, with 2 apical plumose setae; palp, article 2 longer than articles 3 and 4 combined, article 4 with 1 long distal seta.
Male (sexually dimorphic characters).Based on paratype, male, 4.4 mm, NMV J71521.Pereopods without oostegites.oblique facial row of plumose setae on outer margin; outer plate with a row of apical plumose setae.Maxilliped inner plate subrectangular, apical margin with 4 robust setae and several plumose setae, medial margin lined with many plumose setae; outer plate sub-equal in length to palp article 2, with 9 robust setae and row of plumose setae on medial and facial margins, with 5 apical plumose setae; palp, article 2 longer than articles 3 and 4 combined, article 4 with 1 long distal seta.
Variation.The gnathopod 1 coxa anterior margin can be either produced or subquadrate to weakly produced (produced, paratype hermaphrodite "c", AM P.100395; subquadrate to weakly produced, holotype, hermaphrodite "a", AM P.100393).The gnathopod 2 propodus palm appears to vary with growth stage, with the palm posterodistal shelf becoming more pronounced in larger specimens (8.3 to 13.3 mm, AM P.100393 and AM P.100394, respectively).
Remarks.The shape of pereopods 6 to 7 bases in C. sprightly sp.nov., is ovate, the merus, carpus and propodus have bunches of long, distal plumose setae, the carpus posterodistal corner has 6 submarginal robust setae and uropod 2 outer ramus has a brush of about 20 plumose setae on the outer ramus.This set of characters separate C. sprightly sp.nov.from all other Australian species.
Distribution.Australia.Western Australia: City Beach, Dongara, Bluff Point and Cliff Head, (current study).

Discussion
The absence of Chevaliid species in the Australian and New Zealand biogeographic regions was notable enough to gain mention in Barnard's 1972 1).An identification key to separate all 19 species of Chevaliidae is provided.
The New Zealand species, Bryoconversor tutus is known from seven localities giving some insight that Chevaliid species may have large distribution ranges.Similarly, Chevalia burrewarra ranges from northern New South Wales to southern Victoria.Also, three species, C. bardi sp.nov., C. csiro sp.nov.and C. sprightly sp.nov., in Western Australia are from nearby collection localities, indicating that species co-occur.
The sexual dimorphism for Chevalia species described here include female, male and intersex.Males were defined as those individuals with enlarged gnathopods, penes present and oostegites absent.Females as individuals with either large or small gnathopods, penes absent, oostegites present.Females included both ovigerous and non-ovigerous specimens, where ovigerous females appeared to have a broader basis on pereopod 7. Intersex was defined as individuals with enlarged gnathopods, penes and oostegites present, ovigerous or non-ovigerous.
It is unclear from the specimens at hand if individuals maintain as a single sex or transition from one gender to another during their lifecycle (either as a progressive development or environmentally induced need in the absence of the opposite sex).Intersex material has been documented elsewhere for closely aligned Corophioidea, Corophiidae and Ischyroceridae (Sexton & Reid, 1951;Just pers. comm. 2008) and more distant groups such as Lysianassoids and Hadzioids, namely Conicostomatidae, Gammaridae and Maeridae (Lowry & Stoddart, 1983;Pastorinho et al., 2009;Hughes, 2011).Within the Amphipoda there may be naturally occurring, parasitic or environmentally induced intersex individuals (Ford & Fernandez, 2005).Intersex amphipods have been shown as reproductively functional (McCurdy et al., 2004) and the existence of two intersex states, having either an internal or external phenotype, for feminized males (Short et al., 2012).Reproductive strategy is little known from most amphipod species yet given the frequency of intersex in the material observed here and previously for the original records of B. tutus by Lörz et al., 2014, a functional reproductive strategy or high parasitic load are more plausible intersex drivers within the Family Chevaliidae, based on intersex individuals being from multiple locations and across species.

Figure 1 .
Figure 1.Distribution map of Australian and New Zealand Chevaliidae species.Stars represent type localities; circles represent additional data points.

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The generic diagnosis is modified from Souza-Filho et al., 2010 in order to accommodate C. freycinet sp.nov.and C. sprightly sp.nov.The expanded character range includes: the mandible with article 3 slightly shorter and now includes subequal to article 2; and also, coxae 1 to 7 being either disjunct or contiguous.The character of coxae 1 and

Figure 2 .
Figure 2. Field guide to Australian and New Zealand Chevaliidae species.

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Chevalia bardi sp.nov.can be differentiated from C. burrewarra sp.nov., C. csiro sp.nov., C. freycinet sp.nov.and C. sprightly sp.nov.by the presence of many setae on the basis of gnathopod 2. In C. bardi sp.nov. the gnathopod 1 basis has convex margins while the gnathopod 2 basis margins are straight separating it from other species (in this study) where the gnathopod bases have a similar shape.Chevalia bardi sp.nov.can be separated from C. csiro sp.nov.by the subovate bases of pereopods 5 to 7 whereas C. csiro sp.nov.has subrectangular bases.Chevalia bardi sp.nov.has a much larger body size, 20 mm, than C. csiro sp.nov., 5.8 mm, with which it co-occurred.
Distribution.Australia.Western Australia: west of Dongara (current study).
summary of region biodiversity.In the present study, investigation of material from Western Australia, Victoria, Tasmania and New South Wales, has recognised 5 new species, Chevalia bardi sp.nov., C. burrewarra sp.nov., C. csiro sp.nov., C. freycinet sp.nov.and C. sprightly sp.nov., described here in.Seven species have now been recognised from Australia and New Zealand bringing the total number of Chevaliid species to 19 (Table