Dellichthys morelandi Briggs, 1955

Conway, Kevin W., Stewart, Andrew L. & Summers, Adam P., 2018, A new species of sea urchin associating clingfish of the genus Dellichthys from New Zealand (Teleostei, Gobiesocidae), ZooKeys 740, pp. 77-95 : 89-91

Dellichthys morelandi Briggs, 1955

Material examined.

All New Zealand. Gisborne: NMNZ P.001574, holotype, 35.8 mm SL; Lottin Point. Auckland: AIM MA995, 1, 38.8 mm SL; Waitemata Harbour, Torbay Reef (36°41'42.0"S, 174°45'42.0"E), 13 May 1968. - AIM MA5414, 5, 28.0-36.2 mm SL; Waitemata Harbour, Okoromai Bay, Whangaparoa Peninsula, 22 January 1985. - AIM MA27860, 1 (DNA voucher), 18.7 mm SL; Waterfall Bay, Manukau Harbour (37°01'44.4"S, 174°32'17.9"E), 9 April 2008. Chatham Islands: AIM MA 93927, 1, 45.4 mm SL; Waitangi Ellice Point (43°56'36.0"S, 176°33'54.0"W), 28 March 1995. Northland: AIM MA5198, 2, 35.2-36.0 mm SL; Whangaruru, Bland Bay (35°20'24.0"S, 174°22'24.0"E), 22 February 1984. - AIM MA5331, 3, 27.5-42.7 mm SL; Bay of Islands, Urapukapuka Island, Albert Passage (35°13'18.0"S, 174°14'36.0"E), 22 August 1984. - AIM MA5345, 2, 31.5-32.7 mm SL; Cape Wiwiki, Bay of Islands (35°09'36.0"S, 174°07'36.0"E), 23 August 1984. - AIM MA7024, 5, 22.8-60.5 mm SL; Te Puna off Mataka, Bay of Islands (35°09'0.0"S, 174°06'12.0"E), 20 March 1988. - AIM MA77665, 1, 51.6 mm SL; Deep Water Cove, Bay of Islands (35°11'42.0"S, 174°18'0.0"E), 8 September 1992. - AIM MA656096, 1, 27.4 mm SL; Three Kings Islands, Great Island (34°09'08.9"S, 172°07'50.5"E), 18 April 2013. - NMNZ P.018388, 15 (2 C&S), 29.0-46.4 mm SL; Motukokako Island (35°09'00.0"S, 174°20'00.0"E), 8 February 1986. - TCWC 17173.03, 1, 21.0 mm SL; Matapouri, Mermaid Pool (35°33'32.1"S, 174°30'51.3"E), 2 March 2015. - TCWC 17174.03, 1, 23.7 mm SL; Tutukaka, Dolphin Bay (35°37'33.4"S, 174°32'33.4"E), 2 March 2015. - TCWC 17264.02, 3, 20.0-33.8 mm SL; Tutukaka, Pacific Bay (35°37'07.2"S, 174°32'03.8"E), 8 March 2016. -TCWC 17264.02, 3, 21.0-35.0 mm SL. -TCWC 17269.03, 1, 37.1 mm SL; Rawhiti, Taupiri Bay (35°16'58.4"S, 174°17'38.0"E), 10 March 2016. - TCWC 17615.04, 3, 18.2-32.0 mm SL; TCWC 17615.14, 2 (C&S), 18.5-22.0 mm SL; Tutukaka, rocky bay between Tutukaka reserve and Kukutauwhao Island (35°36'40.7"S, 174°32'29.8"E), 11 March 2016. Southland: AIM MA6548, 1, 42.8 mm SL; Chalky Sound (46°03'0.0"S, 166°31'0.0"E), 23 May 1986. Wellington: NMNZ P.030622, 4, 28.1-65.5; Castlepoint, Wairarapa (40°54'00.0"S, 176°14'00.0"E), 14 December 1992. - NMNZ P.030626, 5 (2 CT, 1 male [https://doi.org/10.17602/M2/M37807], 1 female [https://doi.org/10.17602/M2/M37808]), 41.4-61.4; same as NMNZ P.030622, 11 November 1992.

Diagnosis.

Dellichthys morelandi is diagnosed by the following combination of characters: snout spatulate, long (length greater than interorbital distance); lower jaw shorter than upper jaw; teeth at tip of upper jaw visible in gap between upper and lower lip at tip of jaws when jaws are closed; patch of teeth on lingual surface of premaxilla roughly triangular, with ~90 small conical teeth; skin fold on surface of snout located at approximately one quarter of the distance from snout tip to anterior margin of eye, widely separate from fold of upper lip by a broad band of thin, transparent skin; postorbital lateral line canal pore 2 located anterior to imaginary horizontal line through preopercular lateral line canal pore 3; dorsal and lateral surface of head light brown to bright orange or red in life; body light brown to dark orange, red or purplish in life; faint brown reticulate markings on median fins in life.

Remarks.

Briggs (1955) described D. morelandi based on 14 specimens all from Lottin Point (East Cape). Though we have examined more specimens than were available to him, the morphometric and meristic characters reported herein (Table 1) are consistent with those in the original description.

Briggs (1955:14) made several observations on the snout of D. morelandi , which he described as "protruding, spatulate" and “distinctive”. Briggs (1955) made no mention of sexual dimorphism in relation to the snout of D. morelandi but based on the material that we have examined there is a clear difference in snout shape between the sexes, with males possessing wider snouts than females when viewed from above (Fig. 10). In addition to a wider snout, males also exhibit a wider head than females, which may be related to an increase in the size of the muscles of the adductor mandibulae complex. These differences in snout and head profile between the sexes do not appear to be mirrored in the cephalic skeleton, which is similar in males and females (Fig. 10). Sexual dimorphism in head and snout shape has been reported for a number of gobiesocids (e.g., Guitel 1888; Pfaff 1942; Sakashita 1992), is likely related to male nest guarding and parental care (e.g., Coleman 1998; Pires and Gibran 2011), and is probably more widespread than known currently within this fascinating group of fishes.