Common names:

* proposed name

Synonyms:

Etymology:
'Periophthalmus' is a compound name from the Greek 'peri' (around), and 'ophthalmôn' (eye), which refers to the wide visual field of these species

the specific name is after Charles Darwin, after whom Darwin Harbour (where the holotype was collected) was named (Larson & Takita, 2004)

Maximum recorded length:
45 mm SL (Larson & Takita, 2004)

Live colouration (Larson & Takita, 2004, pers. obs.: Australia NT, Papua New Guinea):
background colour light brown to greyish on dorsum and flankes, ventrally whitish; head with dark brown streaks and mottling on dorsum, ventrally white; 7-8 dorsal dark brown saddle-like diagonal and irregular bars, usually well evident; dark brown blotches between bars may be present. D1 light brown basally, medially dark brown, and with a transparent margin; D2 transparent with two parallel series of dark brown speckles on elements: the medial series can be expanded into a medial brown stripe; caudal fin dusky, with series of brown speckles along rays; anal fin hyaline; pelvic fins whitish ventrally, dorsally brownish; pectoral fins hyaline with brownish rays

Colouration on preservation (Larson & Takita, 2004; pers. obs.):
ground colour dorsally and laterally grey to light brown, ventrally paler; chin and isthmus may be brownish; dark dorsal banded pattern and blotches usually visible; D1 brownish with a transparent margin; D2 transparent with two series of dusky speckles, or a dusky medial stripe and a proximal series of dusky speckles on elements; caudal fin dusky with series of brown speckles on rays; pectoral fins dusky; pelvic and anal fins whitish

Diagnosis (Larson & Takita, 2004):
total D2 elements 11-13; total anal fin elements 12-14; pectoral fin rays 11-14; longitudinal scale count 58-78; predorsal scales 20-30; pelvic fins united for half their length, with a distinct pelvic frenum, and with tips pointed to bluntly pointed; D1 greatly reduced in both sexes (depressed D1 length 5.1-9.6% of SL; spines IV-VI), and widely separated from D2.
The genus is yet undefined by synapomorphies

Diet (pers. obs.: Australia, NT, Papua New Guinea):
carnivorous; it can be frequently observed chasing crabs and other small invertebrates; no published study is available

Reproduction:
no published study is available

Ecological notes (pers. obs.: Australia NT, Papua New Guinea):
locally very abundant in the intertidal zone, along mud banks of tidal creeks and inlets, never far from mangrove trees. P. darwini forms dense aggregations, and seems to be relatively less aggressive than other congeneric species

left: bank of a tidal creek: here P. darwini was found on top of the vegetated banks and inside the forest at low tide (Purutu Is., Fly river delta, Papua New Guinea)

right: a small stand of Avicennia and Rhizophora spp. along a small stream at low tide. Also here P. darwini was always found nearby the trees (Doctor's Gully, Darwin, Northern Territory, Australia)

(photos, left: A. Sacchetti, 2007, with permission; right: G. Polgar, 2007)

Distribution (Larson & Takita, 2004):
recorded from northern Australia; found also in the Fly river delta, Papua New Guinea (pers. obs.); type locality: Shoal Bay, Australia, NT

Photographs of Periophthalmus darwini:

A: holotype of P. darwini (NTM-S-10554-004) (photo: G. Polgar, MAGNT, Darwin, Northern Territory, Australia, 2007); B, C: a burrow with its owner nearby a small creek at low tide (photos: G. Polgar, Vestey's Creek, Darwin, Northern Territory, Australia, 2007); D-G: P. darwini in a small mangrove forest, at low tide (D, E), and at high tide (G), perching on a mangrove trunk (photos: G. Polgar, Doctor's Gully, Darwin, Northern Territory, Australia, 2007); H: another specimen on a creek's mud bank (photo: G. Polgar, Purutu Is., Fly river delta, Papua New Guinea, 2007); I, J: other shots of P. darwini on a creek's mud bank (photo: G. Polgar, Buffalo Creek, Northern Territory, Australia, 2007); K: P. darwini preying a small crab (photo: G. Polgar, Ludmilla Creek, Darwin, Northern Territory, Australia, 2007)

Drawings of Periophthalmus darwini:

left: cephalic sensory and nasal pores of Periophthalmus spp.: an= anterior nostril; pn= posterior nostril (modified from Murdy, 1989)* - * with permission