Trachelochismus aestuarium Estuary Clingfish, new species.
Creators: name: King, Cragen
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Actinopterygii
Gobiesociformes
Gobiesocidae
Trachelochismus
Trachelochismus aestuarium

description: Trachelochismus aestuarium, new species.
Estuary Clingfish
Figs. 2, 3, 4A,B, 5A,B, 6
Trachelochismus sp.; Stewart (2015:1543, couplet 12, Fig. 24)
Holotype. NMNZ P.057566, 24.0 mm SL; New Zealand, Northland, Ngunguru River estuary at Ngunguru, 1–2 meters depth, 35°37.78'S 174°30.41'E, 0 9 March 2016, I. Middleton, K. W. Conway, S. Hannam, G. Short, T. Trnski.
Paratypes. All New Zealand. North Island: Auckland: AIM MA451, 2, 29.1 –35.0 mm SL; Waitemata Harbour, Papakohatu (Crusoe) Island, 36°49'0.0"S 174°58'0.0"E, 0 4 May 1931.— AIM MA3082, 1, 37.4 mm SL; Whangateau Harbour between Emu Point and Motuihe Island wharf, 36°48'30"S 174°55'36"E, 0 3 July 1979.— AIM MA4968, 2, 26.8–27.8 mm SL; Whangateau Harbour, near entrance to Omaha River, 0–2 meters depth, 20 June 1982.—AIM MA76154, 1, 24.0 mm SL; Waitemata Harbour, Emu Point, 36°47'49.0"S 174°54'44.1"E, 24 March 1933.— AIM MA30483, 1, 39.1 mm SL; Hauraki Gulf, Buckland Beach at Tamaki Estuary, 36°52'00.0"S 174°54'04.3"E, October 2011.— AIM MA80711, 2, 23.2–29.2 mm SL; Waitemata Harbour between Motuihe and Motutapu, 18 meters depth, 36°46'44"S 174°57'48"E, 28 March 1930.— NMNZ P.008053, 2, 41.3–42.5 mm SL; Fairchild Island, North Auckland; 36°26.00'S, 175°47.00'E, October 1955. Bay of Plenty: NMNZ P. 012187, 1, 13.7 mm SL; off south end of Motiti Island, 16–20 meters depth, 37°40.30'S, 176°22.70'E, R/V Tangaroa, Stn. NZOI BS738 /R96, 21 January 1979.— NMNZ P.047977, 12, 21.8–31.8 mm SL; Whangapoua Harbour, East Coromandel, Zostra near mangroves, 36°45.00'S, 175°38.00'E, 16 April 2002. Marlborough Sounds: NMNZ P.024704, 1, 24.3 mm SL; Off Cone Island, D'Urville Island, 15 meters depth, 40°55.30'S, 173°46.20'E, 27 February 1990. Northland: AIM MA77653, 1, 22.7 mm SL; Parengarenga Harbour, Parenga Channel 400 meters west of Ngamungu Point, 1 meter depth, 17 October 1992.— AIM MA80328, 1, 21.3 mm SL; Parengarenga Harbour between Te Pua Point and Dog Island, 0.3 meters depth, 34°31'30"S 172°56'48"E, 17 October 1993.— AIM MA 122277, 6 (2C&S), 25.3–34.0 mm SL; Tauranga Port, 26 March 2015.—AIM MA38045, 1, 30.0 mm SL; TCWC 17172.01, 2, 11.3–24.9 mm SL; same locality as holotype, 14 February 2015.—AIM MA143002, 4, 16.2– 21.6 mm SL; AIM MA 121550, 2, 18.0– 20.5 mm SL; TCWC 17266.03, 2 (1 SEM), 24.6 mm SL; same as holotype.— NMNZ P.008091, 1, 21.9 mm SL; Tauranga Harbour, 37°39.00'S, 176°05.00'E, on Zostra mudflats, August 1956.— NMNZ P.009927, 1, 32.9 mm SL; off Ranganui Bay, rock dredge, 25 meters depth, 34°48.400'S, 173°19.50'E, R/V Tangaroa, Stn. NZOI BS870 /O161, 27 January 1981.— NMNZ P.009933, 6, 10.4–19.9 mm SL; off Spirits Bay, 29 meters depth, 34°25.00'S, 172°46.60'E, R/V Tangaroa, Stn. NZOI BS916 /O662, 3 February 1981.— NMNZ P.009934, 42, 10.1–24.6; off Spirits Bay, 23 meters depth, 34°25.60'S, 172°48.200'E, R/V Tangaroa, Stn. NZOI BS915 /O661, 0 3 February 1981.— NMNZ P.009935, 1, 14.5 mm SL; off Ranganui Bay, 23 meters depth, 34°49.60'S, 173°15.00'E, R/V Tangaroa, Stn. NZOI BS871 /O617, 27 January 1981.— NMNZ P. 012194, 4, 22.5–32.9 mm SL; off Ranganui Bay, 25 meters depth, 34°48.40'S, 173°19.50'E, R/V Tangaroa, Stn. NZOI BS870 /O616l, 27 January 1981.— NMNZ P.024564, 5, 22.6–31.6 mm SL; Hope Passage (Albert Channel), between Rawhiti Point and Cable Bay, 4–6 meters depth, 35°13.00'S, 174°15.00'E, 22 October 1983.— NMNZ P.025328, 1, 30.7 mm SL; Off Ranganui Bay, 23 meters depth, 34°49.60'S, 173°15.00'E, R/V Tangaroa, Stn. NZOI BS871 /O617, 27 January 1981.— NMNZ P.025676, 4, 13.4–25.2 mm SL; Whangarei Heads, 35°49.00'S, 174°30.00'E. — NMNZ P.049305, 1, 20.7 mm SL; Whangarei Harbour, channel NW of Darch Point, 5–7 meters depth, 35°48.90'S, 174°28.80'E, 0 3 April 1997. — NMNZ P.057565, 1, 16.4 mm SL; Estuary at Matapouri below eastern road bridge, 35°34.21'S, 174°30.69'E, 0 2 February 2015.— NMNZ P.057565, 1, 21.3 mm SL; Sand spit side of the Ngunguru River estuary, 0 meters depth, 35°37.98'S, 174°30.35'E, 0 7 January 2015. Waikato: NMNZ P.049204, 1, 29.4 mm SL; Tairua Harbour, 37°00.52'S, 175°51.17'E, 21 February 2001. Wellington: NMNZ P.008060, 2, 22.0– 31.3 mm SL; Wellington Harbour, midway between Ward Island and Eastbourne shore, 4 meter depth, 41°15.00'S, 174°52.00'E, Stn. VUW R/ V Tirohia, BS 272, 18 March 1971.— NMNZ P.008062, 1, 40.2 mm SL; Foveaux Strait, between Stewart Island and Bluff, 46° 32.00'S, 167°46.00'E, 0 4 November 1970.— NMNZ P.008064, 1, 38.9 mm SL; Foveaux Strait, between Stewart Island and Bluff, 46°32.00'S, 167°46.00'E, 0 4 November 1970.— NMNZ P.053660, 1, 45.5 mm SL; Off Days Bay, Eastbourne, 17–20 meters depth, 40°16.95'S, 174°54.00'E. — NMNZ P.049250, 4, 18.0– 31.1 mm SL; Pauatahanui Estuary, Porirua Harbour, low tide channel, amongst Ulva, hand net 0–1 meters depth, 41°06.00'S, 174°54.00'E. South Island: Otago: AIM MA6949, 1, 29.2 mm SL; Otago Harbour, Portobello Bay, 4-5 meters depth, 45°50'00.0"S, 170°39'54.0"E, 0 6 January 1988.— NMNZ P.008058, 1, 28.4 mm SL; Portobello, Otago Peninsula; 45°50.00'S, 170°39.00'E, 13 August 1962.— NMNZ P. 012302, 1, 22.8 mm SL; Portobello, Otago Peninsula, 15 meters depth, 45°50.00'S, 170°39.00'E, 0 9 November 1952.— NMNZ P.054768, 1, 32.7 mm SL; Portobello Bay, Otago Peninsula, 1 meter depth, 45°49.38'S, 170°39.74'E NIWA Stn. SVDUD2287, 0 5 August 2003. Tasman: NMNZ P.008065, 1, 25.4 mm SL; Puponga, North-west Nelson; 40°31.00'S, 172°44.00'E; 5–11 m; FM Climo, 10 Mar 1971.
Diagnosis. A species of Trachelochismus distinguished from its congeners by the following combination of characters: adhesive disc region A without flattened papillae at centre; apapillate area of adhesive disc region A equal in width or wider than region C; flap along posterior margin of anterior nostril a short, thin blade; lachrymal canal pores 2 and 3 flush with surface of skin or weakly elevated above skin; suborbital, mandibular and postorbital rows of superficial neuromasts located in shallow grooves with smooth borders; suborbital row continuous, extending along ventral margin of orbit; postorbital row with 3 superficial neuromasts; a single gill raker along the anterior edge of ceratobranchial 1; 8 dorsal-fin rays; 7 anal-fin rays; 25 pectoral-fin rays; 32 vertebrae (14 + 18); in life, a single dark brown or black irregular streak on lateral surface of head posterior to eye.
Description. General body shape as in Figure 2. Morphometric characters listed in Table 2.
Head large, slightly dorsoventrally compressed. Body moderately dorsoventrally compressed anteriorly, becoming increasingly laterally compressed posteriorly at region of dorsal and anal fins. Widest point of head wider than widest point of body (immediately behind head). Body width and depth tapering gradually posteriorly. Eye large, positioned on dorsolateral surface of head; orbit visible in ventral view. Centre of eye closer to tip of snout than to posterior margin of operculum. Snout short, broad, anterior margin rounded. Anterior nostril a small tubular opening, with short, thin blade-like flap extending from posterior margin. Posterior nostril tubular, situated along anterdorsal margin of orbit. Gill membranes united and free from isthmus.
Mouth terminal, large; posterior tip of upper jaw reaching imaginary vertical line through centre of orbit when mouth closed. Upper lip fleshy, narrowest at centre; separated from snout by shallow groove. Lower lip fleshy, narrowest at centre, expanded into large lobes adjacent to lower jaw symphysis; lobes extend ventromedially to border anterior margin of mandibular rows of superficial neuromasts. Premaxilla with outer row of larger conical teeth with slightly recurved tips and medial patch of 20–30 smaller conical teeth on lingual surface adjacent to symphysis. Dentary with broad patch of conical teeth with slightly recurved tips anteriorly, tapering to single row of conical teeth posteriorly. Pharyngeal jaws comprising patch of 18–21 small conical teeth with slightly recurved tips on pharyngobranchial toothplate 3 and three rows of 6–11 small conical teeth with slightly recurved tips along ceratobranchial 5. 5–8 gill rakers located along anterior and posterior edge of ceratobranchials 2–3 and anterior edge of ceratobranchial 4; 1 gill raker located along anterior edge of ceratobranchial 1 (absent on either left or right side in two C&S specimens examined). Gill filaments associated with ceratobranchials 1–4 (3.5 gill filaments of Briggs, 1955); ceratobranchial 1–3 each with holobranch; hemibranch only on ceratobranchial 4. Basihyal spatulashaped; anterior edge tipped with cartilage. Branchiostegal rays 6; two anteriormost rays articulating medially with hyoid bar along anterior ceratohyal; posterior rays articulating with hyoid bar laterally, including 3 along anterior ceratohyal and 1 straddling junction between anterior and posterior ceratohyals.
Cephalic lateral-line system with 2 pores in nasal canal; 2 pores in postorbital canal; 3 pores in lachrymal canal; 3 pores in preopercular canal; 3 pores in mandibular canal. Second (LC2) and third (LC3) lachrymal canal pores flush with surface of skin or weakly elevated above skin surface. Suborbital, postorbital and mandibular rows of neuromasts located within shallow grooves; borders of grooves smooth, without paired-fleshy swellings adjacent to superficial neuromasts. 11–12 superficial neuromasts in suborbital row; 3 superficial neuromasts in postorbital row; 4–5 superficial neuromasts in mandibular row. Suborbital row extending along ventral margin of orbit; continuous.
Dorsal-fin rays 7 or 8. Anal-fin rays 7 or 8. Principal caudal-fin rays 5 + 5, dorsal procurrent rays 8, ventral procurrent rays 8. Pectoral-fin rays 25. Pelvic-fin rays I.4. All fin rays unbranched and segmented. Caudal fin rounded, tips of principal caudal fin rays extended slightly beyond fin margin. Caudal-fin skeleton comprised of upper and lower hypural plates; epural and parhypural triangular and similar in size. Dorsal-fin origin situated slightly anterior to imaginary vertical line through anal-fin origin. First dorsal-fin pterygiophore inserted between neural spines of vertebrae 17/18. First anal-fin pterygiophore inserted between hemal spines of vertebrae 18/19 or 19/20. Total number of vertebrae 32, consisting of 14 abdominal and 18 caudal vertebrae. Ribs 11, associated with vertebrae 3–13. Epicentrals 20, associated with vertebrae 2–21.
Adhesive disc large, double (Fig. 5A); anterior margin smooth; posterior margin weakly crenulated. Disc region A without papillae at centre; lateral margins with 3–4 transverse rows of papillae. Apapillate region of disc region A equal in width or wider than region C. Disc region B with 4–5 transverse rows of papillae. Disc region C with 3–4 rows of papillae. Papillae of disc region A decreasing in diameter towards outer margin of disc. Papillae of disc region B and C decreasing in diameter towards outer margin of inner disc. Dorsal postcleithrum a small, thin bone, irregular in shape; articulating with dorsal face of ventral postcleithrum (Fig. 5B). Ventral postcleithrum larger than dorsal postcleithrum; irregular in shape, wider laterally than medially, with convex anterior and posterior outlines (Fig. 5B). Fimbrae along posteriorlateral margin of ventral postcleithrum well-developed. Ventral postcleithra articulating along ventral midline via a well-developed cap of dense connective tissue. Skin associated with last pelvic-fin ray attaching to base of pectoral fin opposite 4th lowermost pectoral-fin ray.
Colouration. In alcohol, head and body background colour pale yellow, without noticeable markings. In formalin and shortly after initial transfer to alcohol, body with irregular dark red to orange markings covering entire dorsal and lateral surface and ventral surface posterior to adhesive disc (Fig. 2). Head with irregular dark red stripe on lateral surface extending from posterior margin of orbit to point just anterior to operculum; increasing in depth posteriorly. Fins hyaline.
In life, background colour highly variable, ranging from pale pink to green (Fig. 6). Entire dorsal and lateral surface of body and head, and ventral surface of body posterior to adhesive disc covered with light to dark brown erythrophores. Erythrophores responsible for myriad of irregular markings over dorsal and lateral surface of body, ranging from thin dark brown markings that coalesce to form a mottled pattern against lighter background colour, to broader dark brown saddle-like markings along dorsal midline that may or may not extend ventrad over lateral surface of body (Fig. 6C). Dorsal, anal and caudal fins with irregular light to dark brown markings. Pectoral fin transparent. Dark brown to black streak passing through eye on lateral surface of head; increasing in depth posteriorly. Dorsal margin of streak solid; ventral margin irregular, edged in brilliant white (Fig. 6C).
Distribution. Trachelochismus aestuarium is known only from shallow (0–29 meters in depth) bay and estuarine areas along the coast of New Zealand (Fig. 7) usually in association with mixed shell-bryozoan rubble benthic communities. Several paratypes have also been collected in association with Zostra and mangroves. At the type locality in the Ngunguru River estuary at Ngunguru, T. aestuarium is found predominantly in association with spent shells of bivalves over a substrate of fine sand and silt at depths below the low tide mark (0–3 meters in depth). Though T. aestuarium has been collected throughout coastal New Zealand, the majority of specimens have been collected from along the northeast coast of the North Island (Northland, Auckland, Waikato, to the Bay of Plenty).
Etymology. From the Latin aestuarium, a tidal inlet of the sea, reflecting the presence of this species in estuaries. A noun in apposition.
Comparisons. Trachelochismus aestuarium differs most noticeably from T. pinnulatus and T. melobesia by the shape of the flap associated with the anterior nostril, head profile, and live colouration. In T. aestuarium the flap associated with the posterior margin of the anterior nostril is thin and blade-like (Fig. 4A) and does not reach the anterior margin of the orbit when pressed backwards against the head. In T. melobesia the flap is also blade-like but much longer (Fig. 4E), reaching past the anterior margin of the orbit when pressed backwards. In T. pinnulatus, the flap is short (i.e., not reaching the anterior margin of the orbit when pressed backwards) but scallop-shaped, with a broad, crenulated dorsal margin (Fig. 4C). In Trachelochismus aestuarium lachrymal canal pores 2 and 3 are flush with surface of skin, or only weakly elevated above the surface of the skin (Fig. 4A). In T. melobesia and T. pinnulatus these pores are located at the end of short tubes that overlap the dorsal margin of the upper lip when the mouth is closed (Fig. 4C, E). In life, T. aestuarium exhibits a single dark brown to black streak posterior to the orbit with an irregular ventral margin that is bordered by white compared to multiple darkly coloured stripes alternating with thin white stripes radiating from the posteroventral margin of the orbit in T. melobesia and T. pinnulatus.
Trachelochismus aestuarium is further distinguished from T. melobesia by the absence (vs. presence) of papillae along the centre of disc region A (compare Fig. 5A vs. 5E), a greater interorbital width (31–38% HL vs. 18–22% HL), the presence (vs. absence) of gill rakers along the anterior edge of ceratobranchial 1, fewer dorsal-fin rays (8 vs. 11), a greater number of pectoral-fin rays (25 vs. 23) and caudal vertebrae (18 vs. 16), a greater number of superficial neuromasts in the mandibular (4–5 vs. 3) and postorbital rows (3 vs. 2), a continuous (vs. discontinuous) suborbital row of superficial neuromasts (compare Fig. 3 vs. 8), and the absence (vs. presence) in life of a broad solid or broken pinkish marking that is edged with white and extends over most of the dorsal surface anterior to the origin of the dorsal fin (see Plate 7 B in Paulin & Roberts, 1992; Fig. 9 herein).
Trachelochismus aestuarium is further distinguished from T. pinnulatus by the absence (vs. presence) of paired-fleshy swelling associated with superficial neuromasts on the surface of the head and most obviously those located in the suborbital, mandibular and postorbital rows (Fig. 1), by having the suborbital, mandibular and postorbital rows of superficial neuromasts contained within a shallow (vs. deep) groove (compare Fig. 4A,B vs. 4C,D), fewer gill-rakers along the anterior margin of ceratobranchial 1 (1 vs. 3), and by the width of the apapillate area of adhesive disc region A (as wide or wider than region C vs. narrower; compare Fig. 5A vs. 5C).
Uncorrected p distances for the 684 bp sequence of the COI gene analysed herein between T. aestuarium and its congeners range from 4.8 (T. pinnulatus) to 12.9 (T. melobesia) (Table 3).
Phylogenetic Relationships. The phylogenetic position of Trachelochismus aestuarium differed between the topologies resulting from the analyses of the different gene data sets. Trachelochismus aestuarium and T. pinnulatus are sister groups in the topologies resulting from the analyses of the mitochondrial genes (Fig. 9A), whereas T. aestuarium is placed as the sister taxon to T. melobesia + T. pinnulatus in topologies resulting from the analyses of ZIC1 (Fig. 9B). At least one morphological character, the absence of papillae at the centre of adhesive disc region A (a derived condition within Gobiesocidae; K.W. Conway, pers. obs.), provides evidence in support of the hypothesis that T. aestuarium and T. pinnulatus are sister species. Though a detailed investigation of the morphology of the three species of Trachelochismus has yet to be conducted, we are aware of no apomorphic characters that would support the alternative hypothesis that T. melobesia and T. pinnulatus are sister groups.
description: Published as part of King, Cragen, 2017, A new species of the clingfish genus Trachelochismus from bay and estuarine areas of New Zealand (Teleostei: Gobiesocidae), pp. 531-549 in Zootaxa 4319 (3) on pages 534-544, DOI: 10.11646/zootaxa.4319.3.6, http://zenodo.org/record/890384