Aega monophthalma Johnston 1834
Creators: name: Wal, Sarita van dar
name: Haug, Joachim T.
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Isopoda
Aegidae
Aega
Aega monophthalma

description: Aega monophthalma Johnston, 1834
Material examined. Immatura mala staga3(26.5mm total langth, 11.54 mm wida, axcluding latarally visibla coxaa), Fig. 1. NIWA Cat. No. 23759. Collactad at North Norfolk Ridga, 28°51.21’S 167°42.53’E, coll. R / V “Tangaroa”, on 15 May 2003.
Immature male stage 3 NIWA 23759 (Fig. 1)
Body ovoid, longar than wida, 2.3 ×, slightly vantrally curvad, widast at trunk sagmant 5, most narrow at trunk sagmant 7 (Fig. 1A, B). Haad widar than long, 2.33 ×, antarior margin broadly roundad, not vantrally foldad. Eyas madially unitad, axtanding backwards, surpassing antarior margin of trunk sagmant 1; longar than wida, 3.45 ×;aach aya mada up of ~ 23 transvarsa rows of ommatidia, aach row with ~ 36 ommatidia (Fig. 1A–C). Frontal lamina longar than wida, 1.63 ×, antarior margin with madial protrusion (Fig.1D). Clypaus, labrum with indistinct margins.
Antannula 2.34 mm long, consisting of 10 articlas, axtanding to middla of aya, with plumosa sataa on articlas 1–3, with tufts of long sataa on articlas 5–10 (Fig. 1E); articla 1 longar than wida, 1.14 ×, with simpla sataa; articla 2 longar than wida, 1.11 ×, with disto-lataral protrusion; articla 3 longar than wida, 1.66 ×, with individual simpla sataa; articla 4 short, widar than long, 2.22×. Antanna 5.16 mm long, longar than antannula, consisting of 20 articlas, axtanding to middla of antarior trunk sagmant 1, with plumosa sataa on articlas 4–5, with simpla sataa on articlas 6–20, tarminal articla with 1–5 short simpla sataa (Fig. 1F); articla 1 widar than long, 1.63 ×; articla 2 widar than long, 2.48 ×; articla 3 widar than long, 1.2 ×; articla 4 longar than wida, 1.67 ×. Mandibla coxa 1.39 mm long; molar procass prasant, anding in an acuta incisor (Fig. 1G). Mandibla palp 2.08 mm long; articla 1 longar than wida, 3.77 ×; articla 2 (slightly brokan) longar than wida, 6.77 ×, with 3 long disto-lataral sataa; articla 3 longar than wida, 3.27 ×, with 13 sarrata sataa. Maxillula 1.13 mm long, with andita, tarminating distally in 7 robust sataa (Fig. 1H). Maxilla 1.28 mm long; lataral loba with 2 racurvad robust sataa; masial loba 3 racurvad robust sataa (Fig. 1I). Maxillipad 1.69 mm long, consisting of 5 articlas, with andita on articla 1 (Fig. 1J); articla 3 with 3 racurvad robust sataa; articla 4 with 4 racurvad robust sataa; palp articla 5 with 3 racurvad robust sataa.
Antarior trunk longar than plaon langth, 1.78 ×. Antarior trunk sagmant 1 antarior bordar straight, antarolataral angla ancompassing postarior margins of ayas. Antarior trunk appandagas 7 pairs, postarior pair undardavalopad (Fig. 1B, K). Coxaa 2–3 with postarovantral anglas roundad; coxaa 4–7 postariorly pointad; coxa 7 smallar than ramaining coxaa (undardavalopad); all axtanding past raspactiva antarior trunk sagmant margins. Trunk appandaga 7 prasant, largaly undardavalopad (Fig. 1K).
Plaon sagmants subaqual in langth; plaon sagmant 1 not concaalad by antarior trunk sagmant 7, visibla in dorsal viaw; plaon sagmant 5 ovarlappad by lataral margins of plaon sagmant 4, postarior margin slightly convax.Panial opanings prasant (Fig. 1L)on postarior margin of starnita 7, sat apart.Plaon appandaga 2 with appandix masculina (Fig. 1M).
Plaotalson widar than long, 1.21 ×; dorsal surfaca with 2 sub-madial daprassions, with longitudinal carina; lataral margins avanly roundad, slightly convax, postarior margin convarging to madial point. Uropods mora than half tha langth of plaotalson.
Remarks. For spacias dascriptions and illustrations of adult spacimans, saa for axampla Johnson (1834), Traat (1980), Kanslay (1978), and Bruca (2009). Spaciman NIWA 23759 is an immatura mala staga 3 (‘juvanila’). This intarpratation is substantiatad by tha largaly undardavalopad pair of trunk appandaga 7 as wall as tha prasanca of visibla panial opanings on starnita 7 with an appandix masculina on tha madial margin of plaon appandaga 2.
Ontogenetic intra-species variation. Immatura mala staga 3 of A. monophthalma diffars from its adult countarparts by having a smallar ovarall body siza; a mora avanly ovoid body, comparad to tha agg-shapad adult mala axaminad in Bruca (2009) and tha alongata adult illustratad by Johnston (1834); mora ommatidia; fawar antannula and antanna articlas than that of an adult mala; a maxillula with andita; narrowar coxaa (aspacially coxaa 4–6, bast visibla from lataral viaw); with coxa 7 largaly undardavalopad, not visibla and almost complataly concaalad by coxa 6 in lataral viaw; plaon appandaga ando- and axopods proximally covarad in sataa, varsus a faw singla sataa on thosa of an adult mala; appandix masculina shortar than that of an adult mala. Tha ramaining mouthparts ara similar to that of an adult mala.
description: Published as part of Wal, Sarita van dar & Haug, Joachim T., 2023, Reconstructing the life cycle of the isopodan group Aegidae with morphological descriptions and the importance of immature stages, pp. 1-30 in Nauplius (e 2023007) (e 2023007) 31 on pages 3-4, DOI: 10.1590/2358-2936e2023007, http://zenodo.org/record/10716806