Cymadusa drummondae, Hughes, Lauren E. & Peart, Rachael A., 2013

Hughes, Lauren E. & Peart, Rachael A., 2013, New species and new records of Ampithoidae (Peracarida: Amphipoda) from Australian Waters, Zootaxa 3719 (1), pp. 1-102: 33-34

publication ID

http://dx.doi.org/10.11646/zootaxa.3719.1.1

publication LSID

lsid:zoobank.org:pub:1F275DB9-0D3B-4322-9F21-A402F1384D8C

persistent identifier

http://treatment.plazi.org/id/E574A473-FFB3-7E6F-7BC4-84ADFB01F978

treatment provided by

Plazi

scientific name

Cymadusa drummondae
status

sp. nov.

Cymadusa drummondae   sp. nov.

( Figs. 16 View FIGURE 16 , 17 View FIGURE 17 )

Type material. Holotype male, 11.0 mm, dissected, 4 slides, NMVJ 64944, Cape Otway, Victoria (38 ° 52 ’S 143 ° 31 ’E), 28 January 1967, coll. W. Seed; paratype male, 9.4 mm, dissected, 1 slide, NMVJ 64946, Cape Otway, Victoria (38 ° 52 ’S 143 ° 31 ’E), 28 January 1967, coll. W. Seed; paratype female, 8.3 mm, dissected, 1 slide, NMVJ 64945; paratypes 7 specimens, NMV J 18115, Cape Otway, Victoria (38 ° 52 ’S 143 ° 31 ’E), 28 January 1967, coll. W. Seed.

Additional material examined. Victoria: 1 specimen, AM P. 88411, Walkerville South (38 ° 51 ’S 145 ° 59 ’E), 0.5 m, brown algae Padina   sp. and Dictyopteris   sp., 7 December 2010, Coll. A.G.B. Poore.

Type locality. Cape Otway, Victoria, Australia (38 ° 52 ’S 143 ° 31 ’E).

Etymology. Named in honour of Margaret M. Drummond for her contributions to the taxonomy of the Australian amphipod fauna.

Diagnosis. Antenna 1 similar to antenna 2; accessory flagellum 1 -articulate. Antenna 2 article 4 length 1.2 times article 5; flagellum incomplete with more than 28 articles. Mandible accessory setal row with 7 robust setae. Maxilla 1 inner plate with 5 slender setae; outer plate palp slender, with 6 robust setae. Gnathopod 1 coxa distinctly larger than coxa 2, anterior margin convex, anteroventral corner produced rounded; posterior margin with fringe of long, slender setae, with single anterodistal lobe large, rounded; ischium anterior margin with small lobe; propodus subrectangular, palm subacute, convex defined by rounded corner with 1 robust seta. Gnathopod 2 basis shorter than coxa, with single anterodistal lobe large, rounded, not reaching beyond ischium, anterodistal corner with 4 slender setae; ischium anterior margin with lobe; carpus subtriangular, anterior margin with slender setae; propodus subovate, broad, palm subacute, entire, defined by produced subquadrate corner with 1 robust seta; dactylus subequal in length to palm, apically acute, tapering evenly, inner margin crenate. Epimera 1–3 subquadrate, posterior margin straight, posterodistal corner subquadrate. Telson apically rounded with 5 pairs of lateral setae and 1 pair of apical setae.

Description of holotype. Head. Antenna 1 similar to antenna 2; article 1 length 1.1 times article 2 length; article 2 length 2.8 times article 3; primary flagellum incomplete, with more than 32 articles; accessory flagellum 1 -articulate. Antenna 2 article 4 length 1.2 times article 5; flagellum incomplete with more than 28 articles. Mandible accessory setal row with 7 robust setae; palp 3 -articulate; article 2 with 1 slender seta; article 3 length 2.1 times width. Lower lip outer plates with slit; lateral lobes distinctly longer than medial lobes, with apical ducts; mandibular lobes with curved margins, rounded apically. Maxilla 1 inner plate with 5 slender setae; outer plate palp slender, with 6 robust setae.

Pereon. Coxae 1–4 longer than broad. Gnathopod 1 smaller than gnathopod 2; coxa 1 distinctly larger than coxa 2, anterior margin convex, anteroventral corner produced rounded; basis shorter than coxa, posterior margin with fringe of long, slender setae, with single anterodistal lobe large, rounded with 2 robust setae; ischium anterior margin with small lobe; merus posterodistal corners subacutely produced; carpus subtriangular, length subequal to width, 0.8 times propodus length, posterior margin produced to form a subacute lobe; propodus subrectangular, length 1.9 times width, palm subacute, convex defined by rounded corner with 1 robust seta, palm length 0.4 times posterior margin; dactylus subequal in length to palm, apically acute, tapering evenly, inner margin crenate. Gnathopod 2 sexually dimorphic; basis shorter than coxa, with single anterodistal lobe large, rounded, not reaching beyond ischium, anterodistal corner with 4 slender setae; ischium anterior margin with lobe; merus posterodistal margins subacute; carpus subtriangular, length 1.2 times width, 0.8 times propodus length, anterior margin with slender setae; propodus subovate, broad, length 0.9 times width, palm subacute, entire, defined by produced subquadrate corner with 1 robust seta, palm length 0.5 times posterior margin; dactylus subequal in length to palm, apically acute, tapering evenly, inner margin crenate.

Pleon. Epimera 1–3 subquadrate, posterior margin straight, posterodistal corner subquadrate. Uropod 1 long, reaching past uropod 2 rami; peduncle length 3.1 times width, with 7 robust setae, setal fringe ¾ length of peduncle, with large, acute distoventral spine; inner ramus slightly longer than outer ramus, with 2 marginal robust setae; outer ramus slender, length 5 times width, with 4 marginal robust setae. Uropod 2 peduncle with 4 robust setae, without distoventral spine; inner ramus longer than outer ramus, with 1 marginal robust setae; outer ramus with 3 marginal robust setae. Uropod 3 peduncle longer than broad, 1.5 times width, twice rami length, with 1 marginal robust setae, with 8 distal peduncular robust setae, with 2 distal slender setae; inner ramus length 1.2 times width, with 6 distal robust setae, 5 distal slender setae and 1 lateral robust setae; outer ramus subequal in length to inner ramus, with patch of small lateral denticles. Telson subtrapezoidal, apically rounded, with small apical cusps, 5 pairs of lateral setae, 2 pairs of lateral plumose setae and 1 pair of apical setae.

Remarks. Cymadusa drummondae   sp. nov. is distinguished from all other Cymadusa   species by the combination of the gnathopod 2 basis and ischium with broad, anterodistal lobes and the broad propodus, where the length is subequal to breadth. Three Cymadusa   species, C. drummondae   sp. nov., Cymadusa elegantis   and Cymadusa chuwae   have the gnathopod 2 male propodus broad with an entire palm. In C. drummondae   sp. nov. and C. chuwae   , the male gnathopod 1 coxa anterior corner is broad and the propodus is subovid, while in C. elegantis   the coxa 1 anterior corner is subacute the propodus rectolinear. The male gnathopod 2 propodus palm is subacute in Cymadusa drummondae   sp. nov., which separates it from C. chuwae   in which the palm angle is near transverse. The telson of Cymadusa drummondae   sp. nov. is apically subacute with a single pair of apical setae similar to C. elegantis   , whereas the telson of C. chuwae   is apically truncate with several pairs of apical robust setae.

Cymadusa drummondae   sp. nov. is also similar to C. grossimana   in the form of gnathopod 1 and 2. Cymadusa grossimana   has the gnathopod 1 coxa anterior margin less broadly rounded and the carpus is more elongate than C. drummondae   sp. nov. The gnathopod 2 basis anterodistal lobe broadly rounded and concave propodus palm in C. drummondae   sp. nov. further separates it from C. grossimana   which has a subacute basis anterodistal corner and straight palm.

Cymadusa drummondae   sp. nov. is very similar to another Australian species, Ampithoe mantissa   sp. nov. in the form of the male gnathopod 2 basis, carpus and propodus, as well as the telson setation. The presence of the large distoventral spine on uropod 1 and accessory flagellum of antenna 1 of C. drummondae   sp. nov. readily separates these species as well as placing them in separate genera.

Distribution. Australia. Victoria: Cape Otway (current study); Walkerville South (current study).