Andhracoides, Wilson, George D. F. & Reddy, Yenumula Ranga, 2011
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publication ID |
https://doi.org/ 10.5281/zenodo.207632 |
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DOI |
https://doi.org/10.5281/zenodo.6191561 |
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persistent identifier |
https://treatment.plazi.org/id/03F50154-FA26-FFB3-FF75-FD4A7269FA0D |
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treatment provided by |
Plazi |
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scientific name |
Andhracoides |
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gen. nov. |
Andhracoides View in CoL gen. nov.
Type species. Andhracoides shabuddin , sp. nov., here designated. Currently monotypic.
Etymology. The prefix of the generic name, “Andhra” alludes to the Andhra Pradesh State in peninsular India, where the new genus has been found. The Latin suffix for likeness “oides”, an adjective with one termination, with “c” retained, is taken from the hypsimetopid genus name Phreatoicoides Sayce, 1900 . The gender of Andhracoides is considered masculine.
Diagnosis. Head. Frontal process above antennula ( Fig. 3 View FIGURE 3 A; dorsal margin of antennal notch) not curved. Pereon pereonite 1 dorsal margin in lateral view shorter than on pereonite 2 ( Fig. 2 View FIGURE 2 A). Pereonites 2–7 in dorsal view anteriorly longer than wide, decreasing posteriorly to wider than long. Coxal articulation to pereonites 2–4 nearly fused, 5–7 free. Pleotelson shallow (lateral fields sloping), lateral margin in dorsal view linear, broadening posteriorly ( Figs 2 View FIGURE 2 D, 9A), dorsal surface in lateral view weakly curving, length substantially greater than width of uropodal insertion, lateral margin with fine setae only; posterolateral margin in lateral view uninterrupted, without distinct inflection differentiating apex, crenate, with 4 teeth, teeth rounded in cross-section ( Figs 2 View FIGURE 2 D, 9D, G); posterior apex in dorsal view projecting posteriorly (not indented), dorsal margin of ventral anal ring projecting posteriorly ( Fig. 9 View FIGURE 9 C); dorsal surface without setose tubercles. Antennula and Antenna elongate with numerous flagellar articles. Antennular distal articles ( Fig. 3 View FIGURE 3 D) in cross-section circular; terminal article tubular, shorter than penultimate article; penultimate article not distinctly longer than other articles, width approximately subequal to antepenultimate article width. Antenna article 1 absent, article 5 longer than article 4, article 6 subequal to articles 4 and 5 combined ( Fig. 3 View FIGURE 3 C, E). Mandible. Palp article 3 medial surface naked ( Fig. 4 View FIGURE 4 A). Right lacinia mobilis with two dentate plates (smaller plate on anterior surface of larger plate) ( Fig. 4 View FIGURE 4 E). Spine rows with bifurcate spines, forming strongly convex arc in ventral view, protruding medially, basal insertions curving dorsally to posteriorly ( Fig. 9 View FIGURE 9 B– D). Molar process stout, heavily keratinised; complex setulate spines forming posterior row ( Fig. 9 View FIGURE 9 D). Pereopods. Pereopod I not sexually dimorphic, male and female pereopods similar; dactylus without distal accessory spines ( Fig. 6 View FIGURE 6 A–B); propodus without developed palm, margin convex to straight; without spines or rugose cuticular pad, cuticular fringe weakly developed; with only stout conical simple setae; merus distodorsal margin in cross-section shelf-like and U-shaped. Pereopods II–III ( Fig. 6 View FIGURE 6 C–D) dactylus shorter than propodus, with 1 distal accessory claw and no additional distal spines; propodus without articular plate on posterior side of limb. Pereopods II–IV ( Fig. 6 View FIGURE 6 C–E) basis lateral face ridge absent; ischium dorsal margin with simple setae, none robust. In male. Pereopod IV simple (not prehensile); propodus articular plate on posterior side of limb absent, basis dorsal ridge in cross-section angular and produced but not forming distinct plate. Pereopods V–VII ( Fig. 7 View FIGURE 7 A–B) dactylus with accessory claw ventral to primary claw; propodus articular plate on posterior side of limb absent; basis dorsal ridge angular in cross-section, not distinctly separated from basis shaft, with no large setae; lateral face ventral ridge present, setae absent. Pereopod VII ischium dorsal ridge without flange. Pleopods II–V ( Fig. 8 View FIGURE 8 B–F) exopod proximal article distolateral lobes shorter than distal article; exopod I lateral proximal lobe absent; endopods unilobed; without setae on margins; protopods medial margin coupling hooks absent. Pleopod II endopod appendix masculina ( Figs 7 View FIGURE 7 D–E, 8C) geniculate, projecting laterally at base of appendage; basal musculature pronounced; proximal half of shaft broadly concave in ventral cross-section, not forming tube; distal tip acutely rounded, margins smooth; medial and lateral margins with stiff elongate setae. Uropod ( Fig. 9 View FIGURE 9 A–B, F–H) protopod margin with rounded denticles, dorsomedial ridge in dorsal view parallel to ventral margin, robustly curving to oppose pleotelson posterior margin, distomedial margin without spinose or robust setae. Endopod subequal to protopod length, straight dorsally, dorsal margin without robust setae or spines on dorsal margin.
Remarks. This genus was originally thought to be part of the Nichollsia clade, but its pleotelson is sufficiently divergent that we have assigned it to a new genus in the family Hypsimetopidae Nicholls, 1943 . Nichollsia has two similar described species N. kashiense Chopra & Tiwari, 1950 and N. menoni Tiwari, 1955 (although N. menoni would benefit from a revision). Moreover, we have found that the morphology described above applies to several undescribed species of Andhracoides gen. nov., found in Andhra Pradesh. The general pleotelson form of this genus, being flattened and broadening posteriorly with a well-developed terminal tip, is unlike any other hypsimetopid, which are either indented or at least transverse in dorsal view. Indeed, Andhracoides is unique among the Phreatoicidea in having a pleotelson that is not strongly vaulted, and therefore much more like other isopods in being rather flattened. We do not think, however, that this condition is basal because the pleotelson is similar to that seen in other Hypsimetopidae ; for example, the postanal margin, which is present in other phreatoicideans and members of other families, is missing, as is typical for other members of this family. The terminal projection of Andhracoides is an extension of the anal ring and, like many other hypsimetopids, has dentition along the pleotelson posterior margin. Moreover, the males of Andhracoides species lack the enormously elongate uropodal exopods possessed by Nichollsia adult males. The exopod is reverse to this condition, with the male exopod being shorter than in the female ( Fig. 9 View FIGURE 9 ).
A phylogenetic analysis of 65 phreatoicidean species and 421 characters (Wilson, in progress; data available on request; see Wilson, 2008 for details) finds that Andhracoides gen. nov., is sister to Nichollsia , as expected, and this group forms a clade with the two species of Pilbarophreatoicus Knott and Halse (one undescribed). Additionally, the hypsimetopid part of the cladogram is similar to that shown in Wilson (2008: fig. 4) but the position of Hyperoedesipus is moved to be sister to the Phreatoicoides – Hypsimetopus clade and the Pilbaran-Indian clade ( Andhracoides , Nichollsia , Pilbarophreatoicus ) emerges basally in the hypsimetopid clade. These results support the biogeographic relationship between India and Western Australia, if based on tectonic vicariance, suggests that these lineages are older than 135 million years ( Wilson, 2008, table 2).
In his introduction, Gupta (1989:1) writes "In a personal communication to Dr. K. K.Tiwari, Prof. P. J. Sanjeeva Raj of Madras Christian College, Tarnbaram (Madras), informs that he has material of phreatoicid isopods from Andhra Pradesh (locality not revealed) in South India obtained during deep drilling operations for boring tube wells." This is almost certainly the first report of Andhracoides gen. nov. but further details have not appeared in the published literature. A conference abstract ( Messana, 2004) mentions a species from Andhra Pradesh referred to Nichollsia ; this species belongs to Andhracoides but is a different species with a heavily setose pleotelson. Its locality is reported to be Belum Cave (Messana, pers. comm.). Gupta (1989) mentions that Nichollsia has been recorded from a number of isolated localities in Uttar Pradesh and Bihar in the Gangetic Plains. These two genera appear to be isolated by major river systems in these two states.
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