Helochares oculatus Helochares (s. str.) oculatus Novochares pallidus Novochares abbreviatus Novochares oculatus Revision of the Neotropical water scavenger beetle genus Novochares Giron & Short (Coleoptera, Hydrophilidae, Acidocerinae) Short, Andrew Edward Z. Giron, Jennifer C. ZooKeys 2023 2023-07-20 1171 1 112 8Y6QW 3A838842-620D-58D3-BDA9-4E5F64A8D010 (Sharp, 1882) Sharp 1882 Insecta Hydrophilidae Novochares CoL Animalia Novochares oculatus Coleoptera 0 1 Arthropoda species oculatus   Figs 3B , 9A-E , 10B   Helochares oculatusSharp, 1882: 74.  Helochares (s. str.) oculatusSharp, 1882;  Fernandez1982a: 31 [specific rank confirmed; not syn. of Novochares pallidusCastelnau, as in  d'Orchymont1926: 232; not. syn. of Novochares abbreviatusFabricius, as in  d'Orchymont1936: 10; lectotype designated];  Fernandez1989: 148 [in key]; Hansen 1999: 162 [catalog].  Novochares oculatus(Sharp, 1882);  Gironand Short 2021: 205.  Type material examined.   Paralectotype(male): " Helocharesocu-/ Novochares latusD.S./ Paso Antonio. Guate/mala Champion [on card with specimen]", "Sharp Coll./ 1905.-313", "Paso Antonio,/ 400 ft./ Champion.", "B.C.A. Col. I. 2./ Helochares/ Novochares oculatus,/ Sharp.", "Brit.Mus./ USNM-1966/ EXCHANGE" (USNM; Fig. 9E).  Additional material examined  ( 8 exs.).  Belize: Stann Creek, Sitte Point, Possum Point Biological Station, 24.iv.1987, leg. P.J. Spangler(1, USNM).   Colombia: Magdalena:  8 kmE Barranquilla, 19.iii.1969, leg. P. & P. Spangler(1, USNM).   Mexico: Jalisco: Barra de Navidad, 23.iii.1971, leg. J.R. Zimmerman(1, USNM).   Oaxaca:  31 kmS Tuxtepec, Bethania, Ao. Chopan, 24.v.1981, blacklight, leg. P.J. Spangler(1, USNM);   Sinaloa: Mazatlan, 17.vii.1963, leg. P.J. Spangler(1, USNM).   Panama: Canal Zone, Barro Colorado Island, vi.1939, leg. J. Zetek(2, USNM), same locality but 29.v.1940, at light (1, USNM).  Differential diagnosis. The precise morphological boundaries of this taxon are still uncertain. Its primary characteristic within the species group is its relatively large and oval distal cup of the dorsal plate of the median lobe, which bears two long arms (Fig. 9A, B). However, there is much variation and we recommend a relatively conservative approach in making confirmed species identifications at this time (see remarks for further discussion).  Description. Body length 6.0-6.5 mm. Coloration: Dorsal surfaces pale brown to orange-brown, sometimes with weakly paler (orange) clypeus and margins of pronotum and elytra. Head: Maxillary palps nearly 1.3 xwidth of head, uniformly yellow to orange in color. Thorax: Elytra without rows of serial punctures, faint rows (one dorsal and two or three lateral) of scarce and weakly marked systematic punctures barely noticeable. Prosternum medially broadly convex. Posterior elevation of mesoventrite broadly elevated, with low medial longitudinal ridge extending anteriorly. Abdomen: Apical emargination of fifth ventrite moderately deep and relatively narrow. Aedeagus: (Figs 3B, 9A-D) Outer margin and apical region of each paramere rounded at apex and laterally pointed to hook-shaped; dorsal plate of median lobe with long and narrow neck, obliquely explanate at apical region, somewhat diamond-shaped and laterally rounded, with two laminate and slender distal arms, narrowly separated at base, apically converging, and slightly dorsally pointing; arms nearly as long as base of fork; ventral plate of median lobe triangular, moderately sclerotized.  Distribution. Belize (new record), Colombia (new record), Costa Rica, Guatemala, Mexico (confirmed record), Panama (Fig. 10B). All records from southern South America and the Caribbean need further review (Argentina, Brazil, Paraguay, and the Antilles [Grenada, St. Vincent]).  Remarks. The identity of this species has been wrapped up in confusion with  N. abbreviatusalmost immediately after it was described (see above discussion of the  Novochares abbreviatusgroup nomenclature). We examined the dissected male lectotype and a dissected male paralectotype male deposited in the USNM (Fig. 9D, E; it had been exchanged between USNM and the British Museum in the 1960s). We saw a number of other specimens that had an  Novochares oculatus-like aedeagus but with a range of variation around the precise shape and size of the apical region of the dorsal plate of the median lobe, as well as the shape of the paramere apices (Fig. 9F, H). We did not have good sampling of these forms for molecular data, so were not able to use an integrated approach to explore this variation. Consequently, we have taken a very conservative approach and identified only male specimens which had genitalia that very closely matched the type material as  N. oculatus. The remaining material will need to wait until more data, especially genetic data, is available. There are a number of published records of  N. oculatusfrom Argentina, Paraguay, and southern Brazil (  Fernandez1982a; Clarkson and Ferreira Jr 2014), and while it is very much possible that  N. oculatus(like  N. abbreviatus) is a very widespread Neotropical species, these reports should be treated as unconfirmed until molecular data from those localities is available. 1987-04-24 P. J. Spangler Belize Possum Point Biological Station Sitte Point 1 Stann Creek 1969-03-19 P. & P. Spangler Colombia 8 km E Barranquilla 1 Magdalena 1971-03-23 J. R. Zimmerman Mexico Barra de Navidad 1 Jalisco 1981-05-24 P. J. Spangler Mexico Ao. Chopan Bethania 1 Oaxaca 1963-07-17 P. J. Spangler Mexico Mazatlan 1 Sinaloa 1939-06 1940-05-29 1939-06 J. Zetek Panama Barro Colorado Island Canal Zone 1 Sinaloa