Idiotropiscis lumnitzeri Kuiter, 2004

Short, Graham A. & Trnski, Thomas, 2021, A New Genus and Species of Pygmy Pipehorse from Taitokerau Northland, Aotearoa New Zealand, with a Redescription of Acentronura Kaup, 1853 and Idiotropiscis Whitley, 1947 (Teleostei, Syngnathidae), Ichthyology & Herpetology 109 (3), pp. 806-835 : 827-828

Idiotropiscis lumnitzeri Kuiter, 2004

Figures 12–13 , 15 ; Tables 2–5

Idiotropiscis lumnitzeri Kuiter, 2004: 165 , fig. 1 (Henrietta Head, La Perouse, Sydney, New South Wales, Australia); AMS I.38660-001 (holotype).

Diagnosis.— See generic diagnosis. Idiotropiscis lumnitzeri differs from its congeners by the following combination of characters: strongly elevated supraoccipital; large, prominent, and raised bony dorsomedial crest on the supraoccipital, dome-like in lateral view, protruding anteriorly; posterolateral margins of post-temporal bones expanded moderately anteriorly taking the form of tapered and winglike protuberances; rim of orbit projecting dorsolaterally; one large and blunt spine on cleithral at level of last pectoral-fin ray; small spine posterolateral to pectoral fin; superior trunk ridge with enlarged spines projecting dorsolaterally on 6 th and 10 th trunk rings; subdorsal spines four, last two superior trunk ridges ending under dorsal fin with subdorsal spines, first two superior tail ridges under dorsal fin with subdorsal spines.

Description.— Morphometric and meristic characters listed in Tables 2–4 . Superior trunk and tail ridges discontinuous below dorsal-fin base, lateral tail ridge present, inferior trunk ridge ends at anal ring, lateral trunk ridge confluent with inferior tail ridge. Head large relative to body, angled ventrally 25° from the principal body axis, the anterodorsal profile conoid in lateral aspect; rising steeply from short snout to a prominent supraoccipital; large, prominent, and raised bony dorsomedial crest on the supraoccipital, domelike in lateral view, dorsocaudal margin irregular, protruding anteriorly; posterolateral margins of post-temporal bones expanded moderately anteriorly taking the form of tapered and wing-like protuberances ( Fig. 14C ); cleithral ring distinct, prominent, discontinuous mid-dorsally; anterior nuchal plate absent; posterior nuchal plate present anterior to cleithrum with dorsomedial crest-like ridge along its dorsum, large gap present between the supraoccipital and posterior nuchal plate; cleithral ring distinct, low, discontinuous middorsally at bony dorsomedial crest; rim of orbit projecting dorsolaterally; opercular ridge low, entire, angled dorsally toward gill opening; swelling of gular region ventroposterior to eye forming a transverse pair of blunt protuberances; pectoral-fin base without distinct ridges, on strongly elevated ventrolateral bulge ( Fig. 15 ); trunk narrowest at 3 rd and 4 th ring; dorsum of 2 nd, 3 rd, and 4 th trunk rings noticeably broader than 5–11 th trunk rings; dorsal-fin base strongly raised dorsally; subdorsal rings four (spans two and a half trunk rings and one and a half tail rings), dorsal-fin base starting immediately posterior to 10 th trunk ring and ending immediately posterior to 2 nd tail ring; caudal fin absent. Body spines: large spine present on cleithral ring at level of last pectoral-fin ray ( Fig. 15A ); small spine present posterolateral to the pelvic fin ( Fig. 15A ); superior trunk ridge with enlarged spines projecting dorsolaterally on 6 th and 10 th trunk rings; subdorsal spines four, last two superior trunk ridges ending under dorsal fin with subdorsal spines, first two superior tail ridges under dorsal fin with subdorsal spines ( Fig. 15B ); large simple and branched dermal flaps present on anterior part of frontal ridge, ventral to eye, 4 th and 7 th superior trunk ridges, 7–9 th lateral and inferior trunk ridges, and on 5 th, 10 th, 15 th, 19 th, and 24 th superior and inferior tail ridges. The female specimen (AMS I.45395-001) exhibits well-developed ossification of the skeleton, including the strong ossification of the inferior and ventral trunk area as detected by µCT scanning ( Fig. 13D ). Idiotropiscis lumnitzeri exhibits strong sexual dimorphism associated with the presence of a male brood pouch. The brood pouch is formed along the ventral midline of the tail and is present below the anteriormost 11 tail rings ( Fig. 12D ). µCT scans revealed the brood pouch is enclosed by 11 arcuate bony extensions ( Figs. 13C , 15B ), which extend ventrolaterally from the anterior ventral plate ridges of the tail, are reduced in size posteriorly, the anteriormost extension and curved posterolaterally relative to the other extensions.

Distribution.— Idiotropiscis lumnitzeri is endemic to the temperate waters of southeastern Australia, from Cabbage Tree Bay, Manly, to Brush Island located south of Ulladulla Harbour, New South Wales ( Kuiter, 2004).

Material examined.— Idiotropiscis lumnitzeri: AMS I. 45395-001, female, 54.0 mm SL, N of Burrewarra Point , S of Batemans Bay , New South Wales, Australia, depth 22 m; CAS HH-0423 , male, 69.9 mm SL, SW of Bare Island , Botany Bay, NSW, Australia, 33°59 ' 33.3 '' S, 151°13 ' 47.3 '' E, depth 18 m, 1 March 2007.

Figures

Fig. 12. Lateral view of preserved specimens of Idiotropiscis spp. redescribed in this study. (A) I. australe, WAM P.33543-001, male, 54.7 mm SL. (B) I. larsonae, NTM S.10805-001, male, holotype, 33.5 SL. (C) I. larsonae, GCRL 21518, female, paratype, 33.0 mm SL. (D) I. lumnitzeri, CAS HH-0423, male, 69.9 mm SL. (E) I. lumnitzeri, AMS I.45395-001, female, 54.0 mm SL.

Fig. 13. Lateral view of µCT scanned skeletons of preserved specimens of Idiotropiscis spp. redescribed in this study. (A) I. australe, WAM P.33543- 001, male, 54.7 mm SL. (B) I. larsonae, GCRL 21518, female, paratype, 33.0 mm SL. (C) I. lumnitzeri, CAS HH-0423, male, 69.9 mm SL. (D) I. lumnitzeri, AMS I.45395-001, female, 54.0 mm SL.

Fig. 15. µCT scanned skeleton of Idiotropiscis lumnitzeri, CAS HH-0423, male, 69.9 mm SL. (A) Osteocranium in lateral view highlighting the ventral cleithral cheek spine and small spine posteroventral of pectoral-fin base. (B) Subdorsal-fin base in lateral view highlighting the one upper and one lower subdorsal spines. Abbreviations: CS, cleithral spine; LSDS, lower subdorsal spine; PLS, posterolateral spine on pectoral-fin base; USDS, upper subdorsal spine.

Fig. 14. Dorsal view of µCT scanned neurocranium of the head of (A) Idiotropiscis australe, WAM P.33543-001, male; (B) Idiotropiscis larsonae, GCRL 21518, male; (C) Idiotropiscis lumnitzeri, CAS HH-0423, male. Abbreviations: BLP, bilateral lobed protuberances; SC, supraoccipital crest.