Hoffmannola hansi Marcus and Marcus, 1967

Dayrat, Benoît, Zimmermann, Sara & Raposa, Melissa, 2011, Taxonomic revision of the Onchidiidae (Mollusca: Gastropoda: Pulmonata) from the Tropical Eastern Pacific, Journal of Natural History 45 (15 - 16), pp. 939-1003 : 988-993

Hoffmannola hansi Marcus and Marcus, 1967

( Figures 22 and 23 )

Hoffmannola hansi Marcus and Marcus 1967: 232–236 , figs 87–95. — Marcus and Marcus 1970: 214, figs 92–93.

Type material

A total of 10 syntypes. One syntype ( NMNH 678419 ): one specimen 25/ 25 mm preserved [leg. and collecting date unknown, but likely P. Pickens or M.A. Hill in 1966]; a label printed on 10 July 2007 indicates that this specimen is the “ holotype ”, however Marcus and Marcus did not designate a holotype in the original description, and the other, older label in the jar does not indicate that this specimen is the holotype, thus, this specimen is regarded here as one of the syntypes. Five syntypes ( NMNH 753653 ): five specimens 28/23 to 20/ 17 mm preserved, leg. M.A. Hill, 22 June 1966; both the old and recent labels indicate that these five specimens are paratypes, however, the old label indicates that these specimens were determined by Hans Bertsch as the paratypes; because Marcus and Marcus did not distinguish a holotype and paratypes in the original description, these specimens are regarded here as syntypes. Four syntypes ( NMNH 753651 ): four specimens 28/23 to 22/ 18 mm preserved, leg. P. Pickens, 12 November 1966; both the old and recent labels indicate that these four specimens are paratypes, however, the old label indicates that they were determined by Hans Bertsch as paratypes; because Marcus and Marcus did not distinguish a holotype and paratypes in the original description, these specimens are regarded here as syntypes. Type locality: El Sahuaral , Sonora, [Gulf of California], Mexico [all syntypes come from El Sahuaral, although the specimen catalogued as NMNH 678415 was collected more specifically from Kino Bay, in El Sahuaral]. Type material condition: all specimens are well preserved; only two specimens ( NMNH 753651 ) were dissected prior to the present study, likely by Marcus and Marcus; two specimens were dissected for the present study [27/ 22 mm, labelled as syntype # 1 in the jar, NMNH 753653 ; 28/ 23 mm, labelled as syntype # 2 in the jar, NMNH 753651 ] .

Additional material examined and dissected

Mexico, Sinaloa, Mazatlan , N of Gauiola Beach, 1 December 1953, three specimens 28/23 (#1) to 23/14 (#2) mm preserved [leg. L.O. Miles], identified as Hoffmannola hansi by T . M. Gosliner , ( CASIZ 081809 ) ; Mexico, Sonora, just N of Ensenada Lalo (a bay just N of San Carlos Bay ), 24 March 1966, one specimen 28/ 25 mm preserved [leg. E. Coan and R. Szal], identified as Hoffmannola hansi by T . M. Gosliner , ( CASIZ 073902 ) [dissected] .

Distribution

Endemic to the Gulf of California: Sonora (original description, Marcus and Marcus 1967; present study); Sinaloa (present study). Marcus and Marcus (1970) only mentioned some material collected by P. Pickens on 12 November 1966 from Mexico, without additional locality information; however, Marcus and Marcus (1970), who only briefly commented on H. hansi and did not provide any new anatomical information, likely only referred to the type material. Marcus and Marcus (1967, 1970) also mentioned San Augustin and Angel de la Guarda Island as two other possible localities, but without any material or vouchers. In any case, H. hansi is known to inhabit the Gulf of California from its northern end (Sonora) to it southern end (Sinaloa).

Habitat

Intertidal. On rocks.

Remarks on the original description

The original description is quite detailed and accurate. Several illustrations help clarify the description: radular teeth, a dorsal view of the visceral cavity, and portions of the male, anterior apparatus are drawn. However, the original description of H. hansi was based on the dissection of only two specimens from one locality (Sonora), and could hardly document individual variation of features that seem to distinguish H. hansi from H. lesliei .

Description of new specimens

Several anatomical systems of H. hansi are similar to H. lesliei (nervous system, pallial organs, septum in visceral cavity, digestive system except for the radular formulae, and the posterior genital organs). Their written description is not provided here again, although some organs, which previously have been illustrated only poorly or not at all, are illustrated here. The description below is based on the non-type specimens as well as the type material, especially the two syntypes dissected for the present study.

External Morphology ( Figure 22 ). Background colour of dorsal notum of live animals brownish to black, with lighter pigments around low papillae. In preserved animals, dorsal colour varies from whitish tan to brown and dark grey. Colour of hyponotum and pedal sole varies from whitish tan to light brown. Size of preserved specimens from 28/23 to 20/ 17 mm. In most individuals, total width of pedal sole greater than total width of hyponotum, left and right sides added (H <S), e.g. 1/15/ 1 mm ( NMNH 753653). On hyponotum, hyponotal line around pedal sole separating hyponotum into inner area (close to foot) and outer area. Distance between hyponotal line and pedal sole varies from one sixth to one quarter of width of hyponotum.

Digestive system ( Figures 22 and 23 ). Radular maximum size 10/ 6 mm, when flattened. Radular formulae vary among individuals ( Table 1). From 100 to 195 rows, and from 430 to 735 teeth per half row.

Marginal glands ( Figure 22 ). From 8 to 14 glands on each side. Glands do not touch each other and form only one row on single frontal plane. Glands from 0.5 to 1 mm in diameter.

Reproductive system: male, anterior parts ( Figure 22 ). No accessory penial gland. No distinct penis inside penial sheath. No distinct, conspicuous papilla at distal end of deferens duct. Penial sheath not covered internally by thick folds. Penial sheath <500 µm in diameter and 6 mm in length. No caecum and no concretions in penial sheath. Deferent duct heavily convoluted (actual loops cannot be counted) from entrance in visceral cavity up to penial apparatus. Number of loops varies among individuals, but always many. Diameter of deferent duct more or less constant along its whole length (∼ 200 µm maximum). Deferent duct forms several loops inside the proximal portion of the penial sheath, makes a U-turn, and then goes back distally toward male opening. Anchor of retractor muscle on the penial sheath near U-turn of deferent duct inside penial sheath. Insertion of retractor muscle in between two walls of septum, close to floor of visceral cavity. Retractor muscle thick and strong, present in all specimens.

Discussion

So far, H. hansi has only been known from the original description, and a few additional notes by Marcus and Marcus (1967, 1970), who only dissected two specimens from the same locality. Five additional specimens were dissected for the present study, which significantly improves our knowledge: the distribution range is extended to the entire Gulf of California, with specimens described here from Sinaloa (southern part of the Gulf); the intra-specific variation within H. hansi , as well as the differences between H. lesliei and H. hansi are better known, especially because it seems that Marcus and Marcus never dissected any specimens of H. lesliei (at least they never indicated that they had done), and their knowledge of H. lesliei was based only on Hoffmann’s redescription of that species.

The original description by Marcus and Marcus and ours are largely in agreement. Marcus and Marcus gave one radular formula (170 × 600–0–600) that fits within the range observed here (100/195 × 430/735–1–430/735). The teeth are illustrated here for the first time with SEM. The nervous system, the posterior genital organs and the course of the deferent duct within the visceral cavity are also illustrated here for the first time. Only large specimens were available for the present study; in all of them, the deferent duct was found to be very highly convoluted. However, given what we know about the variation of this character in other species, it will likely be found that, at least in smaller, younger specimens, the deferent duct is less coiled.

The present study, in which intra-specific variation within both H. hansi and H. lesliei is evaluated, also helps refine our understanding of the key differences between H. hansi and H. lesliei . In particular, a major difference not mentioned by

penial sheath; (E) posterior (female) genital organs; (F) anterior male genital organs. Scale bars: A, 2.4 mm; B, 9 mm; C, 5 mm; D, 2.4 mm; E, 4 mm; F, 0.75 mm. Abbreviations: bm, buccal mass; dd, deferent duct; dg, digestive gland; fgm, female gland mass; hd, hermaphroditic duct; hg, hermaphroditic gland; i, intestine; lc, left cerebral ganglion; lpl, left pleural ganglion; lrpc, left reno-pulmonary complex; mgg, marginal gland; ot, ocular tentacle; ov, oviduct; pc, pericardium; pg, pedal gland; ps, penial sheath; rm, retractor muscle; rrpc, right, reno-pulmonary complex rs, receptaculum seminis; sp, spermatheca; st, stomach; vg, vaginal gland; vs, visceral ganglion.

Marcus and Marcus is the coiling of the deferent duct. In H. lesliei , the deferent duct of large specimens (which are sexually fully mature) is only loosely convoluted with a few loops. In H. hansi , the deferent duct of similar specimens is very highly convoluted. Although the variation of this character is poorly known in H. hansi , this difference will likely remain a valid, important difference. The deferent ducts of H. hansi (Gulf of California) and H. lesliei (Galapagos) differ as much as the deferent ducts differ between Onchidella steindachneri (Galapagos) and O. binneyi (Gulf of California to Ecuador), which have a highly-convoluted and poorly-convoluted deferent duct, respectively. Marcus and Marcus did not see that major difference, likely because they did not have access to any material of H. lesliei , and it is always very difficult to “see” organs in someone else’s descriptions, regardless of whether or not illustrations are available.

Marcus and Marcus (1967) mentioned five differences between H. lesliei and H. hansi . They are commented on here.

(1) According to Marcus and Marcus, the notal glands of H. lesliei are much smaller, more numerous, and on different levels, whereas in H. hansi , the notal glands are larger, less numerous, and not on different levels. Although the size, number, and position of notal (= repugnatory, marginal) glands vary among individuals (see descriptions above), the observation by Marcus and Marcus remains correct.

(2) Marcus and Marcus also claimed that the reno-pulmonary complex is smaller in H. lesliei than in H. hansi . However, that is actually not the case because the width of the reno-pulmonary complex does vary among specimens, and its length relative to the length of the visceral cavity is quite similar between and within each species.

(3) According to Marcus and Marcus, the radulae also differ. However, Marcus and Marcus only knew one formula for H. lesliei (120 × 360–1–360) and one formula for H. hansi (170 × 600–1–600), which might have explained why they differed, but, generally speaking, Marcus and Marcus paid little attention to the individual variation of radular formulae and their impact on taxonomy (see Dayrat 2010a, 2010b). We know now that the range of variation of radular formulae of H. hansi (100/195 × 430/735–1–430/735) and H. lesliei (85/160 × 150/515–1–150/515) overlap partly. So the ranges of radular formulae differ significantly, but must be used with caution because they do overlap.

(4) According to Marcus and Marcus, the penial retractor originates under the nerve-ring in H. lesliei and deep between the two muscles of the septum in H. hansi . However, now that more specimens have been dissected, it seems that the retractor muscle attaches in between the two walls of the septum in both species. However, the retractor muscle of H. lesliei is thin and weak (and it is occasionally difficult to establish its course) and even often absent, whereas it is very strong and always present in H. hansi .

(5) According to Marcus and Marcus, glandular villosities are present in the penial atrium of H. lesliei , which are absent in H. hansi . Such glandular villosities were not observed here, which might be due to the fact that no histology was used.

Figures

Figure 22. External morphology and internal anatomy of Hoffmannola hansi, syntype #1, NMNH 753653, Gulf of California (A–E), and Hoffmannola sp., CASIZ 079295 #1, Pacific Coast of Mexico (F): (A) nervous system and anterior male genital organs; (B) body wall (with marginal glands), visceral cavity, dorsal view; (C) dorsal papillae; (D) deferent duct inside the

Figure 23. Radular teeth of Hoffmannola hansi, Gulf of California: (A) entire radula, syntype #1, NMNH 753653; (B) inner portion of left and right half rows, syntype #1, NMNH 753653; (C) lateral teeth, syntype #1, NMNH 753653; (D) lateral teeth, CASIZ 081809 #2; (E) rachidian tooth, CASIZ 079302 #1, arrow indicates small pointed cusp on outer, lateral expansion of base of rachidian tooth; (F) lateral teeth, CASIZ 079302 #1. Scale bars: A, 1 mm; B, 250 µm; C, 25 µm; D, 25 µm; E, 10 µm; F, 10 µm.