Typhlocarcinops lapillus, 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 : 86-90

publication ID	https://doi.org/ 10.11646/zootaxa.4788.1.1
publication LSID	lsid:zoobank.org:pub:7A461DBA-00B7-48DB-9320-4775DA8F21B2
DOI	https://doi.org/10.5281/zenodo.10564053
persistent identifier	https://treatment.plazi.org/id/03C05222-FFF7-FC55-FF35-D715FAD7FD61
treatment provided by	Plazi
scientific name	Typhlocarcinops lapillus
status	sp. nov.

Treatment

Typhlocarcinops lapillus View in CoL n. sp.

( Figs. 72–75 View FIGURE 72 View FIGURE 73 View FIGURE 74 View FIGURE 75 )

Material examined. Holotype: male (6.0 × 4.2 mm) ( NMCR), station T19, Cortes , Bohol Island, 9°42.2’N, 123°50.8’E, Philippines, coll. PANGLAO 2004, 20 June 2004 GoogleMaps . Paratypes: 5 females (2.5 × 2.0 mm, 2.7 × 1.8 mm, 4.0 × 2.7 mm, 5.8 × 4.0 mm, 5.8 × 4.2 mm) ( ZRC 2018.0280 View Materials ), same data as holotype. Others GoogleMaps : 1 female (4.5 × 2.8 mm) ( ZRC 2018.0281 View Materials ), Tanimbar , Indonesia, 20 m, coll. October 1994 .

Diagnosis. Carapace ( Figs. 72A, B View FIGURE 72 , 74A, D, F, G View FIGURE 74 , 75A, B View FIGURE 75 ) 1.3−1.6 times broader than long, carapace surface smooth, shiny, sparse plumose setae on lateral and frontal margins, regions indistinct; anterolateral margin arcuate, lined with small granules, two shallow indentations anteriorly; posterolateral margin subparallel, entire. Front deflexed, broadly triangular ( Figs. 72B, C View FIGURE 72 , 75B, C View FIGURE 75 ). Orbit ( Figs. 72C View FIGURE 72 , 73G View FIGURE 73 , 75C View FIGURE 75 ) short, bulbous ocular peduncles filling orbit, immovable, cornea small, pigmented. Epistome ( Figs. 72C View FIGURE 72 , 75C View FIGURE 75 ) relatively broad, posterior margin straight, with median suture. Antennal peduncles long. Third maxilliped ( Fig. 73A, H View FIGURE 73 ) with outer surface of merus covered with small granules on distal margin, outer margin straight, anteroexternal angle protruding, auriculiform; ischium squarish, longer than merus; exopod broad. Chelipeds subequal in both sexes ( Figs. 72A, E View FIGURE 72 , 74A, D, F View FIGURE 74 , 75A, F View FIGURE 75 ), smooth, sparse setae on upper and lower margins of fingers and palm; outer lower surface of palm with longitudinal ridge of small tubercles continued to tip of fixed finger, cutting edges of fingers with prominent broad teeth; carpus and merus smooth, margins with long setae; inner angle of carpus with sharp spiniform tooth ( Fig. 74E View FIGURE 74 ). P2−P5 proportionally long ( Figs. 72A View FIGURE 72 , 74A, D, F View FIGURE 74 , 75A View FIGURE 75 ), dorsal and ventral margins fringe with long setae; dactylus straight; merus of P5 not reaching front when folded. Fused thoracic sternites 1, 2 broadly triangular ( Fig. 72D View FIGURE 72 ), proportionally narrow; thoracic sternites 3, 4 partially fused, with only lateral suture discernible. Male pleon ( Figs. 72D View FIGURE 72 , 73B View FIGURE 73 ) relatively broad, telson relatively long, 1.7 times length of somite 6, subtriangular. G1 ( Fig. 73 View FIGURE 73 C–F) slender, curved, upper half shorter, sinuous, distal part curved, tip pointed, one large seta subdistally. Female pleon ( Figs. 74B View FIGURE 74 , 75D, E View FIGURE 75 ) broad, somite 1 reaching coxae of fourth ambulatory legs, tapering to pointed edge; telson subtriangular; vulva ( Fig. 74C View FIGURE 74 ) relatively broad, rounded.

Variation. In the smallest female, the indentations on anterolateral margin form two strong teeth ( Fig. 74G View FIGURE 74 ), while in the large females and males, the anterolateral margin is entire lined with sharper granules ( Figs. 72B View FIGURE 72 , 75B View FIGURE 75 ). The carapace proportions also appear to vary, with one specimen having a proportionately broader carapace ( Fig. 74D View FIGURE 74 ).

Etymology. The name is derived from the Latin “ lapillus ” for a small gemstone, alluding to the small shiny appearance of the species.

Remarks. Typhlocarcinops angustipes and T. lapillus n. sp. both have auriculiform anterolateral angle of the third maxilliped with a broad exopod. There are, however, many differences: the merus of the third maxilliped of T. angustipes is proportionately broader and almost the same length as the ischium ( Fig. 77B View FIGURE 77 ) (versus the merus of the third maxilliped is slightly narrower and much shorter than the ischium ( Fig. 73A, H View FIGURE 73 ) in T. lapillus n. sp.); the male pleon is relatively more narrow with the telson short and semicircular ( Fig. 77C View FIGURE 77 ) (versus the male pleon is relatively broader with the telson long and subtriangular ( Fig. 73B View FIGURE 73 ), in T. lapillus n. sp.), and the upper and lower halves of G1 are subequal, gently curved with scattered setae subdistally ( Fig. 77D, E View FIGURE 77 ) (versus the upper half G1 is shorter, distinctly curved with a large seta subdistally ( Fig. 73 View FIGURE 73 C–E) in T. lapillus n. sp.). The carapace of T. angustipes is also subovate, 1.2–1.4 times broader than long, fringe with long setae on its margin, and with tubercles on the posterolateral surface ( Fig. 76A, B View FIGURE 76 ) (versus the carapace is more ovate 1.3–1.6 times broader than long, sparse setae on its margin and the surface is completely smooth ( Figs. 72B View FIGURE 72 , 75B View FIGURE 75 ) in T. lapillus n. sp.).