(Figs. 1C, 2C, D, 3D–F, 5C, I, 6C, 7C, I, 9E, 10F–J)
Type material. Holotype: male (8.2 × 6.5 mm) (MZB Cru 5449), Kecinan, Lombok, Indonesia, coll. D.L. Rahayu, 9 June 2009. Paratypes: 2 males (4.2 × 3.3 mm, 6.1 × 4.8 mm) (ZRC 2022.91), Nara, Lombok, Indonesia, coll. D.L. Rahayu, 14 June 2007; 1 male (7.0 × 6.1 mm) (ZRC 2022.718), Tanjung Aan, Kuta, Lombok, Indonesia, coll. D.L. Rahayu, 15 May 2014; 1 male (6.5 × 5.6 mm) (MZB Cru 5450), Teluk Nara, Lombok, Indonesia, coll. D.L. Rahayu, 14 June 2007. Others: 1 male (7.0 × 6.2 mm) (ZRC 2022.720), Tanjung Merah, Bitung, North Sulawesi, Indonesia, coll. La Pay, 30 March 2003.
Diagnosis. Carapace subquadrate (Fig. 3D–E); epigastric, hepatic, cardiac and intestinal areolets glabrous, prominent, smooth or almost so; epigastric areolets relatively wide, ovate, not fused with protogastric areolets (Fig. 3D–E); protogastric areolet relatively lower, sometimes covered with setae (Fig. 3D–E); cardiac areolet transverse in position (Fig. 3D–E); hepatic areolet swollen, prominent, proportionately short, reaching only to base of first anterolateral tooth (Fig. 3D–E); external orbital tooth triangular with sharp tip, relatively wide (Fig. 3D–E); tips of anterolateral teeth sharply pointed (Fig. 3C, D); junction between antero- and posterolateral margins demarcated by low sharply pointed or rounded tooth, with low lobe just posterior to it (Figs. 3D–E); epistome relatively wider longitudinally (Fig. 5C); median lobe of posterior margin of the epistome broadly triangular, with lateral margins deeply concave (Fig. 5C). Third maxilliped with merus quadrate, ischium subrectangular (Fig. 5I). Dorsal and lateral surfaces of cheliped carpus with 5 distinct smooth tubercles (Fig. 6C); cheliped fingers not distinctly bent, pollex subparallel with ventral margin of palm (Fig. 7C). P2–P5 not elongate (Figs. 2C, D, 7I); outer surface of P3–P5 merus, carpus and propodus relatively smooth to slightly rugose, and with median longitudinal swelling (Fig. 7I). Male pleonal somites 4–6 transversely narrow, telson wider than long, semicircular in shape (Figs. 9E, 10F). G1 strongly sinuous, distal part relatively shorter, distinctly hooked (Fig. 10G–I).
Colour in life. Carapace and pereopods mostly white, but covered with brown setae; epigastric areolets pale red; protogastric and hepatic areolets pale orange (Fig. 1C).
Etymology. The name is derived from the Latin “sordidus” for dirty, alluding to the general appearance of the species, even after cleaning.
Remarks. Lophoplax sordida n. sp. differs from L. scuplta in that the protogastric areolet is distinctly ovate, relatively lower and can be covered with setae (Fig. 3D–E) (versus more prominent, clearly defined, glabrous and ovate to subcrescentic in shape; Fig. 3A–C); the external orbital tooth is relatively wider (Fig. 3D–E) (versus narrower; Fig. 3A–C); the junction between the antero- and posterolateral margins of the carapace is demarcated by a low sharply pointed or rounded tooth, with a low lobe posterior to it (Fig. 3D–E) (versus junction with two large rounded to subtruncate tubercles with the tips rounded to flattened, often with median depression; Figs. 3A–C, 9A); the male telson is relatively shorter, being wider than long and more semicircular in shape (Fig. 10F) (versus telson longer and more triangular; Fig. 10A); and the G1 distal part is shorter and distinctly hooked (Fig. 10G–I) (versus distal part longer and gently curved; Fig. 10B–D).
Two of the paratype males are smaller than the holotype male, differing mainly in having the areolets slightly less prominent, and the setae on the carapace and pereopods being less dense, the setae being longer and simpler, not appearing spongy (Fig. 3D). The armature of the various body parts, however, is the same.
Habitat. All the specimens were collected from intertidal reef habitats under rocks.
Distribution. Known from the type locality (Lombok Island), and Bitung, North Sulawesi, Indonesia.