Ampithoe eremits, Peart, 2007

Ampithoe eremits sp. nov.

( Figs. 11–13 View FIGURE 11 View FIGURE 12 View FIGURE 13 )

Type material. Holotype: AM P51251, female, ovigerous, 11.0 mm, on algae, Split Solitary Island , Coffs Harbour, NSW, 30°14’30”S 153°10’44”E, 5 Feb 1996, 16 m, I. Takeuchi GoogleMaps . Paratypes: AM P51252, male, 10.5 mm, living on red algae, South Solitary Island , Coffs Harbour, NSW, 30°12’19”S 153°15’54”E, 5 Feb 1996, 12 m I. Takeuchi GoogleMaps ; AM P51253, males and females (5), 8–10 mm, on algae, Split Solitary Island , Coffs Harbour, NSW, 30°14’30”S 153°10’44”E, 5 Feb 1996, 16 m, I. Takeuchi GoogleMaps ; AM P51254, male and females (3), 8– 10 mm, living on red algae, South Solitary Island , Coffs Harbour, NSW, 30°12’19”S 153°15’54”E, 5 Feb 1996, 12 m, I. Takeuchi GoogleMaps .

Diagnosis. Antenna 2 robust, better developed than antenna 1, not densely setose on ventral margin. Lower lip with lateral lobe longer than medial lobe. Maxilla 1 inner plate with three slender setae. Gnathopod 1 carpal lobe subacute; carpus subequal in length to the propodus; palm slightly excavate with a small rounded midmedial tooth, with a small subacute posterodistal tooth defining the palm; dactylus subequal in length to the palm. Gnathopod 2 without densely setose margins; basis posterodistal lobe large and rounded, with more than 3 robust setae; carpus subequal in length to propodus; palm acute, excavate without a midmedial tooth, with a small, subacute posterodistal tooth defining the palm, without a defining robust seta; dactylus subequal in length to the palm. Pereopod 3 basis slightly expanded; merus narrow. Pereopods 5–7 weakly prehensile. Pereopod 5 merus subrectangular. Uropod 3 peduncle with 6 distal robust setae, outer ramus shorter than inner ramus, with patch of small conical lateral denticles, with lateral setal fringe; inner ramus with 7 distal robust setae. Telson distally truncate, apical cusps small.

Description. Based on paratype, male, 10.5 mm, AM P51252. Head as long as deep. Antenna 1 longer than antenna 2; peduncular article 1 longer than article 2 (1.2 x), article 2 longer than article 3 (2.9 x), article 3 shorter than article 1 (0.3 x). Antenna 2 robust, better developed than antenna 1; peduncle article 4 longer than article 5. Mandible molar with 6 robust setae in the accessory setal row; palp stout, long, setose along posterior margin, article 1 shorter than article 2 (0.4 x), article 2 subequal to article 3, article 3 longer than article 1 (2.3 x). Lower lip mandibular lobe with curved margins, subacute apically. Maxilla 1 palp with apical robust setae. Maxilla 2 inner plate narrow, outer plate broader. Maxilliped outer plate with developed setation (robust setae large).

Pereon. Gnathopod 1 subequal to gnathopod 2, without densely setose margins; coxa larger than gnathopod 2 coxa, slightly produced anteroventrally, anteroventral margin produced, rounded, anterior margin convex or straight without setal fringe; basis shorter than coxa, with sparse slender setae, posterodistal lobe large and rounded, with three robust setae; merus produced to form a small, rounded distoventral lobe, anterior margin with setae absent; carpus longer than merus, subtriangular, anterior margin with slender setae only; propodus narrow (length 2.1 x width), ovoid, palm excavate, with small rounded, midmedial tooth, with small, subacute posterodistal tooth defining palm; dactylus subequal in length to palm, inner margin denticulate. Gnathopod 2 without densely setose margins; coxa without setal fringe; basis subequal in length to coxa, with sparse slender setae; merus produced to form a short, subacute distoventral lobe, anterior margin with setae absent; carpus longer than merus, subtriangular, anterior margin with slender setae; propodus broad (length 1.8 x width), ovoid, not produced to form an anterodistally setose lobe; dactylus tapering evenly, acute, inner margin denticulate. Pereopod 5 basis with marginal robust setae, with medial slender setae; distal articles slender; propodus slightly expanded distally, with 3 distal robust setae; dactylus hooked. Pereopod 6 with marginal robust setae, with medial slender setae; basis posterior margin rounded; propodus slightly expanded distally, with 3 distal robust setae; dactylus strongly curved. Pereopod 7 with marginal robust setae, with medial slender setae; propodus slightly expanded distally, with 3 distal robust setae; dactylus strongly curved.

Pleon. Epimeron 3 posteroventral corner narrowly rounded. Uropod 1 peduncle with a short setal fringe; inner ramus longer than outer ramus, with 9 marginal robust setae, slender setae absent; outer ramus with 13 marginal robust setae, slender setae absent. Uropod 2 peduncle with 6 marginal robust setae, setal fringe absent; rami subequal in length; inner ramus with 13 marginal robust setae, slender setae absent; outer ramus with 13 marginal robust setae, slender setae absent. Uropod 3 peduncle longer than broad (1.6 x), short with respect to rami length (2 x), with 2 marginal robust setae, marginal slender setae absent; inner ramus with 7 distal slender setae. Telson with apical slender setae only.

Female (sexually dimorphic characters). Based on holotype, female, 11.0 mm, AM P51251. Antenna 2 slender, similar to antenna 1, not densely setose on ventral margin; peduncle article 4 subequal to article 5; flagellum 28-30 articulate Gnathopod 1 coxa produced anteroventrally, rounded, anterior margin concave; propodus narrow (length 1.6 x width); palm acute, entire, without midmedial tooth, with a single robust setae near inner base of dactylus, with a posterodistal tooth defining palm. Gnathopod 2 propodus broad (length 1.8 x width); palm acute, entire, without a midmedial tooth, with a single robust setae near inner base of dactylus, with a small subacute posterodistal tooth defining palm.

Etymology. The name is Latin for solitary, alluding to the type locality.

Remarks. Ampithoe eremitis sp. nov. is similar to A. caddi Poore & Lowry, 1997 and the species group of A. waialua, J.L. Barnard 1972 , A. ngana Poore & Lowry, 1997 , A. platycera Sivaprakasam, 1970 and A. hinatore J.L. Barnard, 1972 . Ampithoe eremitis and A. caddi both have elongated gnathopods, though differing in structure as follows: the merus of both gnathopod 1 and 2 is produced anteriorly into an acute lobe on A. eremitis , and not so in A. caddi .

The palm structure is more similar to that of species of the Ampithoe waialua species group comprising of A. waialua, J.L. Barnard 1972 , A. ngana Poore & Lowry, 1997 , A. platycera Sivaprakasam, 1970 and A. hinatore J.L. Barnard, 1972 . This group shares an excavate palm on gnathopod 1 in males. Ampithoe waialua and A. ngana both have an anteriorly produced merus on both gnathopods 1 and 2. However, A. eremitis differs from A. waialua by having an excavate palm on gnathopod 2, and by having a more excavate gnathopod 1 palm. The female of A. eremitis also differs from the females of A. waialua by having small posterodistal tooth defining the palms of gnathopods 1 and 2.

The specimens of this new species are also much larger ( 10–11 mm) than those of A. waialua ( 4–5 mm), slightly larger than A. hinatore ( 7–8 mm) and similar in size to A. ngana ( 10–13 mm).

Habitat. Living on red algae in 12–16 m depth.

Distribution. Coffs Harbour, New South Wales, southeastern Australia.