Ozestheria Schwentner, Just & Richter 2015

Genus Ozestheria Schwentner & Richter, 2015 Diagnosis (modified from Schwentner et al. 2015a and Rogers 2020) Populations composed of males and females; amplexus is venter to venter. Umbo present, extending above dorsal margin (supramarginal). Carapace ornamentation highly variable, including lirae, reticulations or smooth ornamentation. Carapace coloration from yellow, to light brown, reddish-brown and dark brown. Head with condyle short or elongate, with wide or narrow occipital notch; frontal organ sessile. Rostrum without posterior margin. Juvenile with rostral spine, absent in adults. Claspers with slender, claw-like projections at the tip of the movable finger. Eggs attaching to prolonged exopods of thoracopods IX and X. Posterior trunk segments with several medial dorsoposterior spines per segment (very rarely last segment spineless). Cercopod with medial longitudinal setal row on proximal 40–60%. Setae plumose and either long or short. Setal row terminates with single spine. Remarks Rogers (2020) listed further diagnostic features, which we exclude from the genus diagnosis because these are either too variable to be diagnostic or we found that the range was greater than indicated in the diagnosis. For example, we excluded the character state “Ocular tubercle smoothly arcuate. Angle between rostrum and frons 150° to 170°.” (Rogers 2020: 22), as the ocular tubercle can be variably expressed and the respective angle can vary from ~90° to 180°. Also, the height-length ratio is in fact much more variable than suggested in the diagnosis (“Carapace valve length ~1.5 times valve breadth (hinge to margin)”; Rogers 2020: 22). Key to the Australian species of Ozestheria Schwentner, Just & Richter, 2015 One of the main characteristics is the length of the condyle, which had previously been used to separate the species into two genera, used here as the first distinguishing characteristic. Three species (O. gemina sp. nov., O. carnegiensis sp. nov. and O. berneyi) had intermediate long condyles; therefore, these are listed twice. 1. Condyle short, rarely dorsally extending, always leaving wide occipital notch (Fig. 25i) ............... 2 – Condyle long, extending nearly to following trunk segment, leaving very narrow occipital notch (Fig. 13b); ornamentation on mid carapace never with well-defined polygonal reticulations (Fig. 24e–g showing reticulations) .................................................................................................. 15 2. Carapace ornamentation dominated by distinctive polygonal reticulations, only crowded growth bands may lack these (and larval valve due to abrasion) (Fig. 25g –h).............................................. 3 – Carapace ornamentation not dominated by reticulations (these may be present dorsally on the carapace); ornamentation including lirae and/or nodules or smooth............................................... 10 3. Ventral margin of carapace nearly straight (Fig. 25b); telsonic spines usually small (Fig. 25m) (larger spines mainly in juveniles) ............................................................................................................... 4 – Ventral margin of carapace widely rounded, not straight (Fig. 15a); telsonic spines usually of varying size (including larger spines also in adults) ....................................................................................... 5 4. 24–27 complete thorax segments; adult telson usually with <15 spines (rarely exceeding 15, juveniles with more spines); largest known Australian species of Ozestheria, adults usually exceeding 10 mm ......................................................................................... O. lutraria (Brady, 1886) – 23–24 complete thorax segments; adult telson with>15 spines; adults reach ~ 9 mm ....................... ....................................................................................................................... O. paralutraria sp. nov. 5. Walls of polygonal ornamentation not regular, single polygons often intermittent or with projections (Fig. 15e); known only from south-eastern Australia ........................................ O. christiani sp. nov. – Walls of polygonal ornamentation never intermittent or with lateral projections, polygons with pit-like appearance (Fig. 22e).................................................................................................................. 6 6. Carapace ornamentation with polygons, which decrease in size and are slightly compressed ventrally within growth bands (Fig. 43a, f); secondary carapace ornamentation pit-like/rounded (visible best under SEM); male rostrum shorter and concentric ridges of carapace less strongly demarcated than in other species; known only from central Western Australia ........................ O. sarsii (Sayce, 1903) – Carapace ornamentation with polygons, which are not compressed ventrally within growth bands (Fig. 22e–g); secondary carapace ornamentation polygonal (visible best under SEM); male rostrum longer (more elongated) and concentric ridges of carapace stronger demarcated than in other species dominated by polygonal ornamentation (the following species are difficult to distinguish morphologically)................................................................................................................................ 7 7. Telson with more spines (> 20, up to 30); shorter carapace (length up to 7 mm); male antennule short, reaching to flagellomeres V–VII (unknown for O. elliptica) ............................................................ 8 – Telson with fewer spines (usually ~20, rarely up to 27); longer carapace (up to 9 mm, but not all individuals reach this size); male antennule longer, reaching to flagellomeres VII–X ..................... 9 8. Spines on mid telson slightly enlarged; furca with several setae; known only from northern Queensland ........................................................................................................... O. henryae sp. nov. – All telsonic spines subequal in length; furca without setae; known only from north-eastern Western Australia ......................................................................................................... O. elliptica (Sars, 1897) 9. 22–23 complete thorax segments; male rostrum apex strongly rounded; occurs in central and eastern Australia .......................................................................................................... O. rubra (Henry, 1924) – 22–24 complete thorax segments; male rostrum apex weakly rounded; occurs in Western Australia ................................................................................................................ O. matuwa sp. nov. 10. Male rostrum apex rounded (Fig. 14h); thorax with ≤ 21 complete segments .................................11 – Male rostrum apex pointed (acute angle) or protruding (Fig. 42j); thorax with ≥ 22 complete segments .......................................................................................................................................... 13 11. Carapace ornamentation on wide growth bands dominated by punctae (Fig. 14f); large number of mostly crowded growth bands (>50); only known from central Western Australia ........................... ....................................................................................................................... O. carnegiensis sp. nov. – Carapace ornamentation on wide growth bands smooth, nodular, with depressions and/or lirae; carapace usually with <20 growth bands ........................................................................................ 12 12. Carapace ornamentation granular, nodular and pit-like, lacking lirae; carapace coloration whitish translucent; furca with many (~14) setae; only known from northern Western Australia ................... .................................................................................................................... O. pellucida Timms 2018 – Carapace ornamentation dorsally smooth or with irregular depressions, from mid-carapace irregular, nodulous and inconspicuous lirae; carapace coloration dark brown (ventrally lighter); furca with few (~1) setae; only known from western Western Australia ....................................... O. richteri sp. nov. 13. Rostrum with small wing-like dorsal flange, anterior margin strongly convex in males, apex protruding (Fig. 42j); carapace length up to 10 mm; known only from central Western Australia ..... .......................................................................................................................... O. rufa (Dakin, 1914) – Rostrum lacking dorsal flange, anterior margin straight or weakly convex, apex pointed or weakly rounded (not protruding) (Fig. 20j); carapace length <8 mm ......................................................... 14 14. Mid-carapace ornamentation includes reticulations dorsally within growth bands, which transition into lirae..................................................................................................... O. berneyi (Gurney, 1927) – Mid-carapace ornamentation dominated by dorsally anastomosing lirae, no reticulations................. ............................................................................................................................... O. gemina sp. nov. 15. Carapace ornamentation dorsally within growth bands smooth (Fig. 45e) ..................................... 16 – Carapace ornamentation dorsally within growth bands with lirae, granular or punctate, never smooth.............................................................................................................................................. 19 16. Most growth lines densely covered with stout setae (Fig. 45g); male rostrum anterior margin convex and apex strongly rounded (Fig. 45j)............................................................................................... 17