Mamilloecia indica, Graves, 2012

Graves, Carol, 2012, Mamilloecia indica (Halocyprididae: Ostracoda) a new genus and species from the Northwest Indian Ocean, Journal of Natural History 46 (9 - 10), pp. 517-556 : 537-544

publication ID

https://doi.org/ 10.1080/00222933.2011.649017

DOI

https://doi.org/10.5281/zenodo.10536937

persistent identifier

https://treatment.plazi.org/id/0E4C87B1-FF93-C152-851B-6B4CAEADFC66

treatment provided by

Felipe

scientific name

Mamilloecia indica
status

sp. nov.

Mamilloecia indica View in CoL sp. nov.

( Figures 7–11 View Figure 7 View Figure 8 View Figure 9 View Figure 10 View Figure 11 )

Type material

Permanent preparations of the dissected holotype and allotype are deposited in the collections of the Natural History Museum, London registration number NHMUK 2011.1625 About NHMUK for the holotype (female) on slides and NHMUK 2011.1626 About NHMUK for the allotype (male) on slides. The remaining 100 female and 100 male paratypes are retained in 80% industrial methylated ethanol registration numbers NHMUK 2011.1627 About NHMUK 1636 About NHMUK for .

Etymology

The specific name refers to the type locality of the Indian Ocean.

Description

The morphological characters of the carapaces and internal structures are listed in Tables 5–12 together with comparative data for the other species described here.

Description of female

Carapace ( Figure 7A–C View Figure 7 ). Mean length 1.88 ± 0.04 mm (n = 100). Carapace of exemplar specimen ( Table 5) length 1.84 mm; height 0.68 m; breadth 0.60 mm. Height: length ratio 37.0%CL, breadth: length ratio 32.6%CL. In lateral view carapace faintly sculptured with parallel lines running at approximately 45 ◦ to ventral surface. Carapace slightly elongated, maximum height just anterior to mid-length. Ventral margin curving smoothly into posterior margin. At mid-height on posterior margin of right carapace tubercular bulge containing asymmetric gland which opens at apex. Posterior dorsal corner of right valve furnished with small pointed spine. Just below posterior dorsal corner of left valve furnished with blunt tubercle with opening of asymmetric gland.

Frontal organ ( Table 5; Figure 7D View Figure 7 ). Frontal organ stem slender, almost straight and longer than limb of first antenna. Capitulum with wide rounded end: dorsal surface naked; distal end of ventral surface covered in small spines. Total length 37.5%CL, much longer than first antenna.

First antenna ( Table 6; Figure 7D View Figure 7 ). Five-segmented. Limb length 22.8%CL. Third segment with dorsal seta 6.0%CL. Fifth segment with five unequal setae; a-seta 14.1%CL; b-seta 14.7%CL; c-seta 14.7%CL; d-seta 15.8%CL; e-seta 20.9%CL with long hairs.

Second antenna ( Table 6; Figure 7E View Figure 7 ). Protopodite 39.4%CL. First exopodite segment about half length of protopodite. Most swimming setae similar in length to protopodite, all but shortest two setae with long hairs distally. Endopodite ( Figure 7F View Figure 7 ) with short, pointed a-seta; b-seta pointed and bare; no c-, d- or e-setae; f- and gsetae, respectively, 16.8%CL and 20.4%CL; h-seta 11.7%CL; i-seta 14.0%CL; j-seta 12.1%CL.

Mandible ( Table 7; Figure 8A–C View Figure 8 ). Coxale toothed edge of pars incisiva with 10 large blunt teeth. Distal tooth list with two large and about 15 small pointed teeth. Proximal tooth list slightly narrower, with two large teeth and about 18 small pointed teeth. Outer margin of toothed edge of basal endite with two large dagger-shaped teeth, second with rounded tip, one pointed tooth and five subserrate teeth. Exopodite represented by moderately long plumose seta inserted on outer margin of basis. First endopodite segment with plumose dorsal seta and four finely spinose ventral setae. Second segment with two ventral and three dorsal setae, all finely spinose. Third segment with seven spinose terminal setae; one very long and robust.

Maxilla ( Table 7; Figure 8D View Figure 8 ). Basal segment with six anterior, one lateral and four posterior setae. Distal segment comparatively short and wide with five bare terminal claw setae, posteriormost longest.

Fifth limb ( Table 8; Figure 8E View Figure 8 ). Ventrally basale with one plumose and five spinose setae, laterally one plumose and two bare setae, dorsally single long spinose seta – remnant of exopodite. First segment with two ventral setae and one dorsal seta, all spinose. Second segment with three unequal, curved terminal claw setae; middle claw longest 4.9%CL.

Sixth limb ( Table 8; Figure 8F View Figure 8 ). Basale with five plumose ventral setae, laterally one plumose seta and one bare seta dorsally. First endopodite segment with one ventral spinose seta. Second segment with one spinose seta ventrally and one dorsally. Third segment with three unequal spinose, terminal claw setae; middle claw longest 11.0%CL.

Caudal furca ( Table 8; Figure 8G View Figure 8 ). Eight pairs of claw setae diminishing in size dorsally; longest claw 11.4%CL.

Description of male

Carapace ( Figure 9A–C View Figure 9 ). Mean length 1.63 ± 0.04 mm (n = 100). Carapace of exemplar specimen ( Table 9) length 1.56 mm; height 0.60 mm; breadth 0.64 mm. Height: length ratio 38.5%CL, breadth: length ratio 41.0%CL. In lateral view carapace faintly sculptured as in female, maximum height just anterior to mid-length. Ventral margin curving smoothly into posterior margin at similar angle to anterior margin. At mid-height on posterior margin of right valve tubercular bulge containing asymmetric gland. Posterior dorsal corner of right valve furnished with small pointed spine. Posterior dorsal corner of left valve furnished with blunt process with opening of asymmetric gland.

Frontal organ ( Table 9; Figure 9D View Figure 9 ). Frontal organ stem straight; shorter than limb of first antenna. Capitulum long, with bulbous distal end. Dorsal surface bare, but proximal ventral surface covered in small spines. Total length 44.2%CL, much longer than first antenna.

First antenna ( Table 10; Figure 9D View Figure 9 ). With five segments. Limb length 38.5%CL. Third segment with dorsal seta 4.6%CL. Fifth segment with five unequal setae; a-seta 19.9%CL; b-seta 33.0%CL; c-seta 9.9%CL; d-seta with short fine hairs 29.5%CL; e-seta 42.3%CL with long hairs.

Second antenna ( Table 10; Figure 9E View Figure 9 ). Protopodite 46.5%CL. Length of first exopodite segment about one-third length of protopodite. All swimming setae shorter than protopodite, all but shortest two setae with long hairs distally. Endopodite with short, pointed, bare a-seta; b-seta pointed with hairs; c-, d- and e-setae all very short; f- and g- setae, respectively, 35.9%CL and 29.2%CL terminally flattened; h-seta short 7.7%CL; i-seta 16.3%CL; j-seta 13.8%CL. Right endopodite ( Figure 10B View Figure 10 ) with elongated clasping organ in form of hook with long proximal shank and very long curved end piece 10.1%CL. Left endopodite ( Figure 10A View Figure 10 ) ‘hook’ much shorter and curved 5.3%CL.

Mandible, maxilla and fifth limb ( Table 11, 12; Figures 10C–F View Figure 10 , 11A View Figure 11 ). Structure and arrangement of setae for mandible, maxilla and fifth limb same as in female.

Sixth limb ( Table 12; Figure 11B View Figure 11 ). Basale with five plumose setae ventrally, one lateral plumose seta and one bare dorsal exopodal seta. First endopodite segment with single, ventral seta. Second endopodite segment with one seta ventrally and one dorsally. Third segment with three terminal setae, two very long, evenly curved ventrally with long hairs 22.1%CL and one bare much shorter seta 4.2%CL.

Caudal furca ( Table 12; Figure 11C View Figure 11 ). Structure and arrangement of furcal claws similar to female; longest claw 14.3%CL.

Intromittent organ ( Table 12; Figure 11C View Figure 11 ). Male copulatory appendage exceptionally long, 26.9%CL, with two oblique muscles.

Remarks

The distinctive features of M. indica are: tubercle at mid-height on posterior margin with rounded opening; maximum height anterior to mid-length; considerable size difference between female and male ( Figures 7 View Figure 7 , 9 View Figure 9 ).

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