Cerapus moonamoona Berents 2023, sp. nov.
Creators: name: Berents, Penelope B.
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Amphipoda
Ischyroceridae
Cerapus
Cerapus moonamoona

description: Cerapus moonamoona sp. nov.
urn:lsid:zoobank.org:act:1D29E8FB-BF85-4DE8-BF77-BFC11132031C
Figs 19–20
Holotype: Male, 5.0 mm, AM P.106377, off Moona Moona Creek, Jervis Bay, New South Wales, Australia, 35°02'54"S 150°41'12"E, airlift on scuba, 8 m, P. B. Berents, 17 November 1981. Paratypes: 1 female, ovigerous, 5.7 mm, AM P.106378, same data as holotype; 1 male, 3.7 mm, AM P.26872, north-east Botany Bay, New South Wales, Australia, 33°58'39"S 151°12'21"E, sandy mud, 7.5 m, State Pollution Control Commission, SPCC Stn. 29, 7 December 1976; 1 male, 4.2 mm, AM P.26875, east Botany Bay, New South Wales, Australia, 34°00'S 151°12'E, 11.6 m, State Pollution Control Commission, SPCC Stn.74, 27 January 1977; 1 male, 4.8 mm, AM P.106380, 1 male 4.5 mm, AM P.106381, off Moona Moona Creek, Jervis Bay, New South Wales, Australia, 35°03'S 150°40'E, silty sand with fine shell fragments, hand dredge on scuba, AU 76, J. Just, P. B. Berents & R. T. Springthorpe, 18 November 1984.
Additional material examined. 5 females, AM P.106379, same data as holotype; 1 female, 6 juveniles, AM P.106382, off Moona Moona Creek, Jervis Bay, New South Wales, Australia, 35°03'S 150°40'E, silty sand with fine shell fragments, hand dredge on scuba, AU 76, J. Just, P. B. Berents & R. T. Springthorpe, 18 November 1984.
Type locality. Off Moona Moona Creek, Jervis Bay, New South Wales, Australia, 35°2'54"S 150°41'12"E.
Etymology. Named for the type locality. Used as a noun in apposition.
Description. Male (based on holotype, 5.0 mm, AM P.106377).
Head. Rostrum short, length 0.2 × head, evenly tapered, apically subacute; lateral cephalic lobe with ventral corner subacute, subocular margin deeply recessed, reaching beyond eye, anteroventral corner acute, ventral margin horizontal, posterior margin vertical. Antenna 1 long, length 0.5 × body length; peduncle without scales; peduncular article 1 longer than article 3, length 1.3 × peduncular article 3, slightly swollen, posterodistal corner not produced; peduncular article 2 anterodistal corner without distal projection; flagellum 5-articulate; article 1 long. Antenna 2 1.3 × length antenna 1; flagellum 5-articulate.
Pereon. Pereonite 1 without lateral keel, without sternal keel. Pereonite 2 with sternal keel. Pereonite 3 without sternal keel.
Gnathopod 1 coxa not fused to pereonite 1, length 1.4 × depth, without anteroventral lobe; basis length 1.7 × depth; carpus broad, length 1.3 × depth with setose posterior lobe; propodus palm extremely acute, with barbed robust setae. Gnathopod 2 carpochelate; coxa not fused to pereonite 2, length 1.7 × depth, without anteroventral lobe or cusp; basis short, broad, length 1.6 × breadth, without anteroproximal group of long slender setae; carpus long, length 1.6 × breadth, broad, palm shallowly excavate, with 2 apical robust setae, anterodistal tooth tiny, located near articulation with propodus, posterodistal tooth long, well defined, length 1.6 × width; propodus slender, curved, length 5.4 × width, without tooth on posterior margin, posterodistal corner smooth, without teeth; dactylus length 0.4 × propodus.
Pereopod 3 coxa with broad anteroventral lobe, not fused to pereonite 3, length 2.7 × depth; basis, length 1.8 × breadth, with proximal, subquadrate anterodorsal corner, with simple setae along anterior margin, without denticles along anterior margin; ischium long, length 1.9 × breadth; merus length 1.1 × breadth, short, with ridges. Pereopod 4 coxa with anteroventral lobe, not fused to pereonite 4, length 2.2 × depth; basis length 1.3 × breadth, with simple setal group midway along anterior margin; ischium long, length 2.3 × breadth; merus long, length 1.3 × breadth. Pereopod 5 coxa, length 1.5 × depth, without patches of small setae, with setae along ventral margin few or absent; merus with anterior lobe extending beyond anterior margin of carpus, posterior lobe with 3 plumose setae; propodus with 2 setae along posterior margin; dactylus short, uncinate with 1 accessory hook.
Pereopod 6 coxa with setal fringe ventrally, without patches of small setae near margins; basis without patch of small setae near anterior margin; merus length 1.7 × breadth; dactylus short, uncinate, with 1 accessory hook. Pereopod 7 coxa with posterodorsal lobe, without patch of small setae; merus length 1.6 × breadth; dactylus short, uncinate, with 1 accessory hook,
Pleon. Pleopods 1–3 biramous, decreasing in size. Pleopod 1 inner ramus 8-articulate; outer ramus 3-articulate, article 1 evenly swollen; Pleopod 2 inner ramus reduced, 1-articulate; outer ramus, broad, 1-articulate. Pleopod 3 inner ramus reduced, 1-articulate; outer ramus broad, 1-articulate. Uropod 1 biramous; peduncle, length 1.5 × outer ramus; rami with distoventral fan of robust setae; outer ramus with lateral row of denticles, without medial setae, with 6 lateral setae, with large apical robust seta, without smaller slender setae; inner ramus, length 0.7 × outer ramus, with 7 medial and no lateral setae, with large apical robust seta. Uropod 2 uniramous, peduncle, length 2.5 × breadth, 4.2 × length of ramus; ramus small with 2 denticles and 1 slender apical seta. Uropod 3 uniramous, peduncle length 1.4 × breadth; ramus with 2 curved hooks. Telson length 0.8 × breadth, cleft to base, each lobe with 11 or 12 anteriorly directed recurved spines in 2 rows.
Female (sexually dimorphic characters). Based on paratype female, 5.7 mm, AM P.106378. Antenna 1 peduncle without scales; flagellum 4-articulate. Antenna 2 flagellum 2-articulate. Pereonite 1 without lateral keel. Pereonite 2–3 without sternal keel. Gnathopod 1, coxa, length 1.4 × depth; basis, length 1.7 × depth; carpus, length 1.3 × depth with setose posterior lobe. Gnathopod 2 subchelate; coxa, length 1.7 × depth; basis, length 1.8 × depth, without medial line of setae; palm extremely acute. Pereopod 5 coxa, length 1.1 × depth. Oostegites from gnathopod 2 to pereopod 5.
Tube. Composed of fine sediment.
Habitat. Marine, 7 – 12 m.
Remarks. Cerapus moonamoona is the only Australian species with peduncular article 1 longer than peduncular article 3 on antenna 1. Cerapus moonamoona and C. alquirta are the only Australian species with the male second antenna 2 longer than antenna 1 and both species have a sternal keel on pereonite 2. Cerapus moonamoona differs from C. alquirta in having 11 or 12 recurved spines on the telson whereas C. alquirta has 8 recurved spines on the telson; C. alquirta lacks a setal fringe on coxa 6; the posterior margin of the carpus and propodus of female gnathopod 2 is more densely setose in C. moonamoona and male coxa 5 is twice as long as wide in C. alquirta compared with 1.5 times longer than wide in C. moonamoona. The tube of C. alquirta is broader at one end and the tube of C. moonamoona is straight.
The male gnathopod 2 of C. moonamoona changes in shape as the male matures. The propodus is curved and slender in males longer than 4.5 mm. The posterodistal tooth of the carpus of gnathopod 2 becomes longer and more strongly defined in males of 5.0 mm. The carpus of gnathopod 2 is more elongate in mature males with the ratio of length to width 1:1.2 – 1:1.3 in males of 3.7 – 4.5 mm and 1:1.6 in males of 5.0 mm. Mature males have 2 apical robust setae on the palm, which is unique to C. moonamoona.
Distribution. New South Wales: Botany Bay and Jervis Bay.
description: Published as part of Berents, Penelope B., 2023, New Species of Cerapus from Australian Waters (Amphipoda: Senticaudata: Ischyroceridae), pp. 381-403 in Records of the Australian Museum (Rec. Aust. Mus.) (Rec. Aust. Mus.) 75 (4) on pages 399-402, DOI: 10.3853/j.2201-4349.75.2023.1879, http://zenodo.org/record/10413874