Typhlocarcinops atimovatae, Ng & Rahayu, 2020

Ng, Peter K. L. & Rahayu, Dwi Listyo, 2020, A synopsis of Typhlocarcinops Rathbun, 1909 (Crustacea: Decapoda: Brachyura: Pilumnidae), with descriptions of nine new species from the Indo-West Pacific, Zootaxa 4788 (1), pp. 1-100 : 57-60

publication ID	https://doi.org/ 10.11646/zootaxa.4788.1.1
publication LSID	lsid:zoobank.org:pub:7A461DBA-00B7-48DB-9320-4775DA8F21B2
persistent identifier	https://treatment.plazi.org/id/03C05222-FF9A-FC37-FF35-D489FB2CF8BE
treatment provided by	Plazi
scientific name	Typhlocarcinops atimovatae
status	sp. nov.

Treatment

Typhlocarcinops atimovatae View in CoL n. sp.

( Figs. 47–49 View FIGURE 47 View FIGURE 48 View FIGURE 49 )

Material examined. Holotype: male (15.9 × 11.9 mm) (MNHN-IU-200-4369a), station CP3584, Chautelier Nosy Be 11, 25º28’S 44º25’E, Madagascar, 203–210 m, coll. Expedition Atimo Vatae, 10 May 2010 GoogleMaps . Paratypes: 15 males (smallest 7.0 × 5.3 mm), 26 females (largest 13.9 × 10.4 mm, smallest 9.0 × 6.6 mm) (MNHN-IU-200-4369b), 4 males, 2 females ( ZRC 2018.0720 View Materials ), same data as holotype GoogleMaps . Paratypes: 1 male (18.2 × 13.1 mm), 1 female (17.4 × 13.4 mm) (MNHN-IU-2010-4370), station CP 3590, southwest Point Barrow , 25°03’S 43°59’E, 300–309 m, south Madagascar, coll. 11 May 2010 GoogleMaps ; 2 males (12.9 × 9.8 mm, 14.1× 10.2 mm), 1 female (11.8 × 8.8 mm) (MNHN-IU- 2010-4359), station CP 3584, southeast of Point Barrow , 25°28’S 44°25’E, 203–210 m, south Madagascar, coll. 10 May 2010 GoogleMaps ; 1 female (6.5 × 4.8 mm) (MNHN-IU-2010-4362), station CP 3584, southeast of Point Barrow , 25°28’S 44°25’E, 203–210 m, south Madagascar, coll. 10 May 2010 GoogleMaps ; 1 male (14.3 × 10.8 mm) (MNHN-IU-2010-4368), station CP 3594, southwest of Point Barrow , 25°07’S 44°01’E, 264–268 m, south Madagascar, coll. 11 May 2010 GoogleMaps ; 1 female (10.2 × 7.9 mm) (MNHN-IU-2010-4365), station CP 3540, Fort Dauphin area , 25°26’S 47°05’E, 189–217 m, south Madagascar, coll. 3 May 2010 GoogleMaps ; 1 male (13.8 × 10.8 mm) ( ZRC 2018.0727 View Materials ), station CP 3583, southwest of Point Barrow , 25°31’S 44°16’E, 216–302 m, south Madagascar, coll. 10 May 2010 GoogleMaps . All specimens collected by Expedition Atimo Vatae.

Diagnosis. Carapace ( Figs. 47A, B View FIGURE 47 , 48A View FIGURE 48 ) about 1.3–1.4 times broader than long, surface with granules anteriorly, posteriorly, regions not indicated; anterolateral margin arcuate, lined with tiny granules, entire or with 2 low dentations forming 3 broad lobes. Front ( Fig. 47B, C View FIGURE 47 ) bilobed, with shallow median cleft, margin of each lobe slightly convex. Orbit ( Fig. 47C View FIGURE 47 ) short, bulbous ocular peduncles filling orbit, immovable, cornea small, slightly pigmented. Epistome ( Fig. 47C View FIGURE 47 ) relatively broad, concave. Antennal peduncles relatively long. Third maxilliped ( Fig. 49A View FIGURE 49 ) with merus broad, anterolateral corner rounded, outer and inner margins straight, ischium as broad as and, longer than merus, inner margin shorter than outer margin, lower margin slightly oblique; exopod relatively stout, tip reaching to just before distal edge of merus, inner margin with distinct tooth. Chelipeds unequal in males, subequal in females ( Figs. 47A, G View FIGURE 47 , 48A, D View FIGURE 48 ), chela smooth; outer surface of fingers with longitudinal ridge on dactylus and fixed finger, continue to palm; outer lower margin of palm with tubercles; cutting edges of fingers with prominent teeth; inner angle of carpus with short sharp spines, one usually longer ( Fig. 47E View FIGURE 47 ). P2−P5 ( Figs. 47A, F View FIGURE 47 , 48A View FIGURE 48 ) proportionally short, fringe by sparse long setae on dorsal and ventral margins; merus of P5 not reaching front when folded. Fused thoracic sternites 1, 2 broadly triangular ( Fig. 47D View FIGURE 47 ), proportionally broad; thoracic sternites 3, 4 partially fused, with only lateral suture discernible. Male pleon ( Figs. 47D View FIGURE 47 , 49B View FIGURE 49 ) relatively narrow, telson long, 1.9 times as long as somite 6, subrectangular with rounded distal margin. G1 ( Fig. 49 View FIGURE 49 C–F) slender, slightly curved, upper half longer than lower half, distal part directed obliquely upwards with pointed tip. Female pleon ( Fig. 48B View FIGURE 48 ) broad, telson subtriangular; vulva ( Fig. 48C View FIGURE 48 ) slit-like, with flap-like sternal vulvar cover.

Etymology. The species is named after the expedition, Atimo Vatae, which is a Malagasy expression for “deep south” of Madagascar. The name is used as a noun in apposition.

Remarks. Typhlocarcinops atimovatae n. sp. is in the same group of species of T. ocularius Rathbun, 1914 , T. hadrotes n. sp., with the carapace more rounded, anterolateral margins entire or almost so, and the male pleon transversely narrow (especially somites 4–6 and telson). In the form of the G1, T. atimovatae n. sp. ( Fig. 49 View FIGURE 49 C–F) is most similar to T. ocularius ; but the posterolateral margin of T. atimovatae n. sp. is more sharply towards the posterior carapace margin ( Fig. 47B View FIGURE 47 ) (versus posterolateral margins gently converging in T. ocularius ; Fig. 45A, B View FIGURE 45 ); the dorsal carapace surface is less prominently convex ( Fig. 47C View FIGURE 47 ) (versus dorsal carapace surface distinctly convex in T. ocularius ; Fig. 45C View FIGURE 45 ); the ambulatory meri are proportionately longer ( Fig. 47A, F View FIGURE 47 ) (versus ambulatory meri proportionately shorter in T. ocularius ; Fig. 45A View FIGURE 45 ); the male telson is relatively longer ( Figs. 47D View FIGURE 47 , 49B View FIGURE 49 ) (versus male telson relatively shorter in T. ocularius ; Fig. 45E View FIGURE 45 ); and the pollex of the major chela is not bent at an angle ( Fig. 47G View FIGURE 47 ) (versus pollex of major male chela strongly bent in T. ocularius ; Fig. 45G View FIGURE 45 ).

From T. hadrotes n. sp., T. atimovatae n. sp. can be distinguished by its more strongly converging posterolateral margins ( Fig. 47B View FIGURE 47 ) (versus gently converging in T. hadrotes n. sp.; Fig. 50B View FIGURE 50 ); the dorsal carapace surface is less prominently convex ( Fig. 47C View FIGURE 47 ) (versus dorsal carapace surface distinctly convex in T. hadrotes n. sp.; Fig. 50C View FIGURE 50 ); proportionately longer male telson ( Figs. 47D View FIGURE 47 , 49B View FIGURE 49 ) (versus male telson distinctly shorter in T. hadrotes n. sp.; Figs. 50D View FIGURE 50 , 52B View FIGURE 52 ); the pollex of the major chela is not bent at an angle ( Fig. 47G View FIGURE 47 ) (versus pollex of major male chela strongly bent in T. hadrotes n. sp.; Fig. 50E View FIGURE 50 ); and most significantly, the G1 with upper half longer than lower half, distal part slightly curved and the tip directed obliquely upwards ( Fig. 49 View FIGURE 49 C–E) (versus G1 with upper half much longer than lower half, much less curved with the distal part straighter, directed upwards and the tip slightly bent, pointed in T. hadrotes n. sp.; Fig. 52 View FIGURE 52 C–H) (see also discussion for T. hadrotes n. sp.).