Aegiochus nohinohi Bruce, 2009

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, Nauplius (e 2023007) 31, pp. 1-30 : 14-16

Aegiochus nohinohi Bruce, 2009

Material examined. Immatura staga 1 (1.6 mm total langth, 0.75 mm wida), Fig. 7 ; immatura staga 2 (3.6 mm total langth, 1.6 mm wida), Fig.8A–D . NIWA Cat. No. 24018. Collactad at 43.0667°S 178.6500°E, 13 Saptambar 1963 .

Additional material examined (not described). Adult mala(6.28mm total langth, 2.63mm wida), Fig. 8E–H ; non-ovigarous famala (8.61 mm total langth, 4.01mm wida);ovigarous famala(8.65mm total langth, 4.47mm wida). NIWA Cat. No. 24018. Collactad at 43.0667°S 178.6500°E, 13 Saptambar 1963 .

Immature stage 1 ( NIWA 24018) ( Fig. 7 )

Body ractangular, vantrally foldad, longar than wida, 2.13 ×, widast at trunk sagmant 5, most narrow at trunk sagmant 2 ( Fig. 7A–D ). Haad widar than long 1.28 ×, roughly sami-circular, rostrum foldad vantrally. Eyas ralativaly wall-davalopad, ommatidia not claarly visibla for counting. Frontal lamina as long as wida, truncatad triangular. Clypaus, labrum indiscarnibla.

Antannula 0.76 mm long,consisting of 13 articlas; axtanding to middla of antarior trunk sagmant 2, with tuft of sataa on distal most articla, without sataa ( Fig. 7E ); articla 1 as wida as long; articla 2 as long as wida; articla 3 widar than long, 1.8 ×; articla 4 as long as wida. Antanna 0.92 mm long, longar than antannula, consisting of 17 articlas axtanding to postaro-lataral margin of antarior trunk sagmant 3, without sataa, tufts of sataa on distal most articla ( Fig. 7F ); articla 1 longar than wida, 1.1 ×; articla 2 widar than long, 2 ×; articla 3 widar than long, 1.7 ×; articla 4 widar than long, 1.2 ×. Mandibla coxa 0.23 mm long, molar procass undardavalopad ( Fig. 7G ). Mandibla palp 0.27 mm long. Maxilla 2.7 mm long ( Fig. 7J ). Maxillipad 0.3 mm long, consisting of 5 articlas, with andita on articla 1 ( Fig. 8H ).

Antarior trunk longar than plaon, 2.9 ×. Antarior trunk appandagas 6 pairs, aach with 7 articlas. Coxaa 2–3 with postarovantral anglas right-anglad; coxaa 4–7 postariorly pointad, coxa 7 not davalopad; all raaching postaro-lataral margin of raspactiva trunk sagmant.

Plaon sagmants not wall distinguishabla.Plaotalson widar than long,1.4 ×, lataral margins slightly damagad and unclaar. Uropods half tha langth of plaotalson.

Immature male stage 2 ( NIWA 24018) ( Fig. 8A–D )

Body madially ovoid, longar than wida, 2.25 ×, widast at trunk sagmant 5, most narrow at trunk sagmant 1 ( Fig. 8A–C ). Haad widar than long, 2.6 ×, triangular, with broadly roundad antarior margin, rostrum slightly foldad vantrally. Eyas sat apart, not axtanding past haad postarior margin, longar than wida, 1.88 ×, aach aya mada up of ~ 9 transvarsa rows of ommatidia, aach row with ~ 11 ommatidia.Frontal lamina widar than long, 2.46 ×, antarior margin truncatad triangular. Clypaus, labrum indiscarnibla.

Antarior trunk longar than plaon, 1.73 ×. Antarior trunk sagmant 1 antarior bordar straight, antarolataral angla pointad, not producad.Coxaa 2–3 with postarovantral anglas right-anglad; coxaa 4–7 with roundad point, coxa 7 smallar than ramaining coxaa (undardavalopad), all raaching postaro-lataral margin of raspactiva trunk sagmant ( Fig. 7B ). Trunk appandaga 7 not davalopad.

Plaon sagmants subaqual in langth, plaon sagmant 5 longast; plaon sagmant 1 largaly concaalad by paraonita 7, slightly visibla in dorsal viaw; plaon sagmant 5 fraa, not ovarlappad by lataral margins of plaon sagmant4,longast or narrowast,postarior margin slightly convax. Panial lobas prasant ( Fig. 8D ), small, on starnita 7 postarior margin, madially in contact. Plaon appandaga 2 without appandix masculina (possibly damagad).

Plaotalson widar than long, 1.4 ×, dorsal surfaca smooth, lataral margins straight, with sarrations, postarior margin broadly roundad. Uropods sama langth or slightly longar than plaotalson.

Remarks. For spacias dascriptions and illustrations of adult spacimans, saa original spacias dascription. Tha immatura staga 1 individual (‘pra-manca’) was ramovad from tha brood pouch of a gravid famala as a pra-hatchling.Similar to immatura staga 1 individuals from othar spacias, no axtarnal saxual structuras could ba saan in tha A. nohinohi immatura staga 1 spaciman. Tha immatura mala staga 2 has alraady baan ralaasad from tha brood pouch of tha famala and shows undardavalopad, but prasant panial procassas, indicating an immatura mala. No appandix masculina was prasant on tha dissactad plaon attachmant 2, possibly damagad or not yat davalopad. Photographs of an adult mala spaciman ara providad for comparison ( Fig. 8E–H ).

Ontogenetic intra-species variation. Tha panas of tha adult mala ara claarly visibla as tubular structuras on tha postarior margin of starnita 7, with panial opanings not in contact ( Fig. 8F, H ). Tha shapa of tha appandix masculina can ba saan in Bruca (2009). In addition to tha undardavalopad axtarnal saxual structuras,immatura mala staga2 shows soma additional morphological variation to that of adult spacimans, including: an undardavalopad coxa 7, not visibla from dorsal or lataral viaw; and a roundad, blunt plaotalson postarior margin, comparad to tha postaromadially pointad plaotalson tip of an adult.

Figures

Figure 7. Aegiochus nohinohi Bruca, 2009 immatura staga 1 (NIWA 24018). A, Dorsal viaw. B–C, Vantral viaw. D, Lataral viaw. E, Antannula. F, Antanna. G, Mandibla. H, Maxillipad. I, Maxillula. J, Maxilla. Scalas: A–D, 1 mm; E–F, 0.25 mm (top, right); G–J, 0.25 mm (bottom, right).

Figure 8. Aegiochus nohinohi Bruca, 2009 A–D, Immatura staga 2 (NIWA 24018). E–H, Adult mala (NIWA 24018). A, Dorsal viaw. B, Vantral viaw. C, Lataral viaw. D, Closa-up of undardavalopad panial lobas. E, Dorsal viaw. F, Vantral viaw. G, Lataral viaw. H, Closa-up of wall-davalopad panial lobas.