Ampithoidae * Author Hughes, L. E. Author Lowry, J. K. text Zootaxa 2009 2009-10-08 2260 1 153 219 https://www.biotaxa.org/Zootaxa/article/view/zootaxa.2260.1.8 journal article 10.11646/zootaxa.2260.1.8 1175-5326 5322208 Cymadusa mariabyrneae Hughes & Lowry sp. nov. ( Figs 23 , 24 ) Type material. Holotype , male, 6.4 mm , 3 slides, AM P76767 outer reef slope, south of One Tree Island ( 23°30.79’S 152°5.181’E ), large sticks of coral rubble, 13.8 m , I. Takeuchi & L.E. Hughes , 28 October 2006 ( QLD 1994 ) . Paratypes : female, 7.0 mm, 3 slides, AM P76768 ( QLD 1994 ) ; 5 unsexed, AM P76769 ( QLD 1994 ) . Additional material examined. One Tree Island: 2 unsexed, AM P76771 ( QLD 1959); 1 unsexed, AM P76770 ( QLD 1960). Etymology. Named for Professor Maria Byrne, director of the One Tree Island Research Station. Type locality. Outer reef slope, south of One Tree Island , Great Barrier Reef , Queensland , Australia ( 23°30.79’S 152°5.181’E ), living on large sticks of coral rubble, 13.8 m . Description. Based on holotype , male, 6.4 mm , AM P76767. Head. Head as long as deep. Antenna 1 and 2 missing. Upper lip lateral margins each with midlateral notch. Mandible molar well developed, triturating, accessory setal row with 6 serrate setae; palp 3–articulate, apically setose and marginally setose; article 1 shorter than article 2; article 2 slightly longer than article 3; article 3 longer than article 1. Lower lip outer plates notched, forming a medial excavation, medial and lateral lobes subequal in size; mandibular lobe with curved margins, rounded apically. Maxilla 1 inner plate with 1 seta; palp article 2 broad. Maxilliped outer plate with row of large robust setae along medial margin. Pereon. Coxae 1–4 deeper than broad. Gnathopod 1 subequal in size to gnathopod 2; coxa distinctly larger than coxa 2, produced, anterior margin concave, anteroventral corner rounded, with a tuft of slender setae in the posteroventral corner; basis anterodistal lobe absent, with 2 slender setae; merus posterodistal lobe subacute; carpus about 2 x as long as broad, subequal in length to propodus, anterior margin with slender setae, posterior margin straight; propodus broad, subtriangular; palm acute, straight, with rounded posterodistal corner, with 1 robust seta defining palm; dactylus subequal in length to palm, tapering evenly, apically acute, inner margin crenate. Gnathopod 2 coxa with a tuft of slender setae in the posteroventral corner; basis without setae, anterodistal corner lobe absent, with 1 slender seta; merus margin with short, subacute anterodistal lobe; carpus shorter than propodus, subtriangular; propodus broad, less than 1.5 x as long as broad, subrectangular, anterior margin with fringe of slender setae; palm acute, excavate, with posterodistal corner subquadrate, without palm defining robust setae; dactylus overreaching palm, tapering evenly, apically acute, inner margin crenate. Pereopods 3–4 basis narrow; merus subequal in length to carpus. Pereopods 5–7 simple. Pereopod 5 without medial slender setae; distal articles slender; propodus not expanded distally, with 1 anterodistal striated robust seta; dactylus slightly curved. Pereopod 6 basis posterior margin straight, with several marginal slender setae; merus distal articles slender; propodus slightly expanded distally, with 1 anterodistal striated robust seta; dactylus slightly curved. Pereopod 7 similar to pereopod 6. FIGURE 23. Cymadusa mariabyrneae Hughes & Lowry sp. nov. , holotype, male, 6.4 mm, AM P76767, One Tree Island, Great Barrier Reef. FIGURE 24. Cymadusa mariabyrneae Hughes & Lowry sp. nov. , holotype, male, 6.4 mm, AM P76767, paratype, female, 7.0 mm, AM P76768, One Tree Island, Great Barrier Reef. Pleon. Epimera 2–3 posteroventral corner broadly rounded. Uropod 1 peduncle with 9 robust setae, without fringe of slender setae, with large, acute distoventral spine; outer ramus length about 8 x as long as broad, with 8 lateral robust setae; inner ramus with 5 lateral robust setae. Uropod 2 peduncle with 4 robust setae; outer ramus with 8 lateral robust setae; inner ramus with 7 lateral robust setae. Uropod 3 peduncle longer than broad, less than 2 x length of rami, without marginal slender setae, with 7 distal and 1 mid-dorsal peduncular robust setae, without distal slender setae; outer ramus with 2 large recurved distal robust setae, with 2 lateral robust setae and 3 lateral slender setae; inner ramus with 1 distal slender and 3 lateral robust setae. Telson subtrapezoidal, apically truncated, with small apical cusp on each distolateral corner, with2 pair of oblique medial slender setae, with 2 pair of lateral slender setae, 2 pair of lateral and 1 pair of apical plumose setae. Female (sexually dimorphic characters). Based on paratype , female, 7.0 mm, AM P76768. Gnathopod 1 subequal in size to gnathopod 2; basis slightly shorter than coxa, with 1 slender anterodistal seta; dactylus slightly overreaching palm. Gnathopod 2 basis anterodistal corner with 2 slender setae; palm straight, with 1 robust seta defining palm; dactylus subequal in length to palm . Habitat. Coral rubble. Remarks. Cymadusa mariabyrneae sp. nov. is most similar to C. aungtonyae Peart 2002 from Thailand , in the form and setosity of male gnathopod 2 propodus. Coxae 2–3 in C. mariabyrneae however, are more subquadrate than in C. aungtonyae . The gnathopod 1 palm is straight in C. mariabyrneae and sculptured in C. aungtonyae . Overall the uropods of C. mariabyrneae are more slender with a greater number of robust setae relative to those of C. aungtonyae . Cymadusa mariabyrneae is superficially similar to the GBR species C. thagaay Peart, 2007a , with respect to the setose anterior margin of the male gnathopod 2. These species differ in two male gnathopod 1 characters: the anterior margin of the coxa which is concave in C. mariabyrneae and straight in C. thagaay ; and the propodus palm which is straight in C. mariabyrneae and sinusoidal in C. thagaay . Distribution. Australia . Queensland : One Tree Island (current study).